Loyola College Question Paper 2007

Loyola College M.Sc. Chemistry April 2007 Structural Inorganic Chemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 25

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FIRST SEMESTER – APRIL 2007

CH 1802 – STRUCTURAL INORGANIC CHEMISTRY

 

 

 

Date & Time: 30/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

Part – A

 

Answer all the questions                                                   (10 x 2 = 20)

  1. What are the factors affecting the formation of ionic compounds?
  2. Which compound does possess high melting point i) FeCl2 ii) FeCl3
  3. What are the different types of close packing of ions?
  4. Why is the bond length of O22+ less than that of O22-?
  5. Why is the bond angle of NH3 greater than that of H2O?
  6. What are n-type and p-type semiconductors?
  7. What is symbiosis? Give an example.
  8. What are the types of defect in solids? Explain with an example.
  9. What are zeolites? Mention their uses.
  10. What are hetero polyacids and homo polyacids? Give an example.

 

Part – B

Answer any eight questions                                                           (8 x 5 = 40)

 

  1. Calculate the volume occupied by ions or atoms in face-centred cubic arrangement.
  2. Explain with examples, the factors favouring the formation of covalent character in  ionic

compounds.

  1. Predict the structure of the following molecules using VSEPR theory.
    (i)XeF2               (ii)ICl4–.
  2. What are the conditions of resonance and give the resonance structure of
    (i) NO2               and (ii) CO32- ion
  3. Explain the postulates of hybridization and discuss structure of
    (i) PCl5 and (ii)   SF6.
  4. How are clathrates prepared? Mention their uses.
  5. Describe the basic principles involved in neutron diffraction studies and give any

two applications.

  1. Explain Lux-Flood concept of acids and bases.
  2. Discuss the structure, properties and bonding of N3P3Cl6
  3. Explain Why Mn3O4 is normal spinel whereas Fe3O4 is an inverse spinel
  4. How are metallocarboranes prepared? Mention any one structure.
  5. What are silicates? How are they classified? Give an example for each class.

 

 

Part – C

 

Answer any four questions                                                             (4 x 10 = 40)

 

  1. Define lattice energy. How is lattice energy calculated theoretically and experimentally?
  2. Explain why the molecule of CO is diamagnetic and NO is paramagnetic, using M.O  theory.
  3. How does band theory explain the conductance behaviour of conductors, insulators  and

semiconductors?

  1. Explain the Pearson’s concept of hard and soft acids and bases, with examples.

Discuss any four applications of this theory.

  1. What is radius ratio? Discuss the structures of (a) NaCl (b) Rutile.
  2. (i) What are Miller indices? Draw (111) and (110) plane                                 (6)

(ii)Apply Wade’s rule to predict the geometry of B10H102-                                (4)

 

 

 

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Loyola College M.Sc. Chemistry April 2007 Quantum Chemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 23

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FIRST SEMESTER – APRIL 2007

CH 1800 – QUANTUM CHEMISTRY

Date & Time: 25/04/2007 / 1:00 – 4:00Dept. No.                                              Max. : 100 Marks

 

 

 

PART-A   ANSWER ALL QUESTIONS (10 x 2 = 20)

  1. The peak in the sun’s emitted energy occurs at about 480 nm. Assuming it to behave as a black-body emitter, find the temperature of the sun’s surface.
  2. What is the de Broglie wavelength of a body of mass 1g traveling at a speed of 100 Kms-1?
  3. Give the Laplacian operator in spherical polar coordinates. What are their limits of integration?
  4. Show that e-ax is an eigen function of the operator d2/dx2. What is the eigen value?
  5. What is a node? Draw the radial distribution plot for 2s orbital of H-atom and indicate where the nodes are.
  6. Define a ‘fermion’ and give an example.
  7. The energy of a particle moving in a cubic box of side ‘a’ is 12(h2/8ma2). What is its degeneracy?
  8. Indicate the difference in the nature of the spectrum of an electron in an atom and the same electron when it is freed from the atom by ionization.
  9. What is Born-Oppenheimer approximation?
  10. Write the Hamiltonian operator for the H2 molecule in atomic units defining each term involved in it.

 

PART-B   ANSWER ANY EIGHT QUESTIONS (8 x 5 = 40)

  1. What is UV catastrophe? Explain how Planck explained the black body radiation.
  2. Draw the correlation diagrams for F2 and CO molecules and explain the nature of bonds.
  3. What is a hermitian operator? Show that the eigen value of a hermitian operator is real.
  4. Explain Bohr’s correspondence principle with a suitable example.
  5. The spacing between adjacent rotational lines in the spectrum of HCl molecule is 6.33 x 1011s-1. Calculate the moment of inertia of HCl molecule and the internuclear spacing

if the atomic masses are H = 1.008 and Cl = 34.97.

  1. Show that [d/dx, x] = 1

(b) What are the values of [x, px] and [L2,Lx]?

  1. What are quantum mechanical postulates? With an example discuss the postulate regarding average or expectation value of an observable?

 

 

  1. Show that the zero point energy for a particle in a 3-D box is three times that of the one in 1-D box.
  2. In solving the H2+ problem using the LCAO method, the lowest energy obtained is given by E+ = (HAA + HAB) / (1+SAB) where A and B refer to the two hydrogen nuclei. Explain each of the integrals in the above equation and their significance.
  3. The force constant of 79Br79Br is 240 Nm-1. Calculate the fundamental vibrational frequency and the zero-point energy of the molecule.
  4. (a) What is a term symbol?

(b)Taking an example of an atomic term symbol explain what information you get    from the three

parts of the symbol.

  1. Explain quantum mechanical tunneling with a suitable example.

 

PART-C   ANSWER ANY FOUR QUESTIONS (4 x 10 = 40)

  1. (a) Discuss Einstein’s theory photoelectric effect

(b) The work function for Cesium is 2.14 eV. What is the kinetic energy and the speed of the

electrons emitted when the metal is irradiated with light of 300 nm?                                  (7+3)

  1. State and illustrate the Pauli Exclusion Principle for the ground state of He atom that wave functions must be antisymmetric in the interchange of any two electrons.

25   Derive the time-independent  Schroedinger equation from the time-dependent equation and show that the property such as electron density is time independent although the wave function describing an electron is time dependent.

  1. (a) Derive the wave function and energy for the particle in a 1-D box.

(b) An aliphatic conjugated diene (linear) has end to end distance of 8.67 Å and it absorbs at 3540 Å. Determine the number of double bonds and hence predict the structure of the molecule.       (7+3)

  1. What is Variation theorem and its usefulness? Apply it to the problem of particle in a 1-D box of length a, by taking ψ = x(a-x) as a trial function for 0≤x≤a. Give your comment on the result.  (4+6)
  2. (a) What are the three important approximations of Huckel-LCAO-MO theory?

(b) Using this theory set up the secular equation and secular determinant for allyl cation and hence

obtain its energy levels.                                                                                                             (3+7)

 

 

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Loyola College M.Sc. Chemistry April 2007 Quantum Chemistry & Group Theory Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 28

FIRST SEMESTER – APRIL 2007

CH 1808 – QUANTUM CHEMISTRY & GROUP THEORY

 

 

 

Date & Time: 25/04/2007 / 1:00 – 4:00         Dept. No.                                                       Max. : 100 Marks

 

 

Part-A   ANSWER ALL QUESTIONS (10 x 2 = 20)

 

  1. Show that eax is an eigen function of the operator d2/dx2 and find the corresponding eigen value.
  2. What is a linear operator? Explain it with a suitable example.
  3. What is zero-point energy? What is its value for a particle in a 1-D box?
  4. Write the time-dependent Schroedinger wave equation for a single particle in 1-D in stationary state.
  5. Draw the radial probability density curves for 3s, 3p, 3d orbitals and mention the number of nodes possible for each.
  6. Calculate the moment of inertia of 1H80Br, which has an equilibrium bond length of 1.41Å.
  7. Explain the following with an example each: (a) a boson (b) a hartree
  8. What is quantum mechanical tunneling? Give an example.
  9. Identify the point groups for the following molecules:

(a) HCl   (b) CS2  (d) CHCl3   (d) SF6

  1. What do x and y represent in the following two irreducible representations and in what way they differ from each other?

C3v    E    2C3    3σv                                     C2h           E    C2         i      σh

 

 

E      2      -1     0          (x, y)                     Bu        1     -1     -1     1        x,y

 

 

Part-B   ANSWER ANY EIGHT QUESTIONS (8 x 5 = 40)

  1. Draw the correlation diagrams for F2 and CO molecules and comment on the nature of bonds.
  2. What is a Hermitian operator? Show that the linear momentum operator is Hermitian.
  3. Discuss the similarities and the differences between the particle in a box and the Simple Harmonic Oscillator models in terms of its wave function and its energy.
  4. Explain with an example: (a) Bohr’s Correspondence Principle (b) Born-Oppenheimer Approximation
  5. In solving the H2+ problem using the LCAO method, the lowest energy obtained is given by

E+ = (HAA + HAB) / (1+SAB) where A and B refer to the two hydrogen nuclei. Explain each of the integrals in the above equation and their significance.

  1. The spacing between adjacent rotational lines in the spectrum of HCl molecule is

6.33 x 1011s-1. Calculate the moment of inertia of HCl molecule and the internuclear spacing if the atomic masses are H = 1.008 and Cl = 34.97.

  1. Ψ = (2a/π)1/4 exp(-ax2) is an eigen function of the Hamiltonian operator for the 1-D SHO. Find the eigenvalue E and express it in terms of the classical frequency ν, where ν = (1/2π)√(k/m) and the constant a = (π/h)√(km).
  2. What is an atomic term symbol? Write the term symbols for the excited configuration 1s22s22p13p1 of carbon.
  3. The bond length of the C-N bond in 12C14N is 1.17 x 10-10 m and the force constant is

1630 Nm-1. Calculate the value of its fundamental frequency and its rotational constant.

  1. Write the Schroedinger equation to be solved for H atom and solve it for its energy using a simple solution, which assumes the wave function to depend only on the distance r and not on the angles θ and φ.
  2. Evaluate the commuters [y, py] and [L2, Lz]. What can you say about their significance?
  3. The reducible representation obtained using the four C-Cl bonds in CCl4 as bases is

Td    E       8C3        3C2        6S4         6σd

4     1         0         0         2

Show by reducing this into irreducible representation using the Td character table given below that the bonds in CH4 are more likely sp3 hybrids.

Td          E          8C3      3C2      6S4       6σd

A1         1          1          1         1         1                                 x2+y2+z2

A2         1          1          1         -1         -1

E           2          -1         2         0         0                                (2z2-x2-y2, x2-y2)

T1          3          0          -1         1         -1         (Rx,Ry,Rz)

T2          3          0          -1         -1         1         (x,y,z)              (xy,xz,yz)

 

 

Part-C   ANSWER ANY FOUR QUESTIONS (4 x 10 = 40)

 

  1. a) Set up the Schrödinger equation for a particle in 1-D box and solve it for its energy and wave function.
  2. b) A cubic box of 10Å on the side contains 8 electrons. Applying the simple particle in a box model, calculate the value of ΔE for the first excited state of this system.                (7+3)

 

  1. (a) The wave function of 1s orbital of He+ is Ψ1s = (1/√π) (Z/a0)3/2 exp(-Zr/a0), where a0 is the most probable distance of the electron from the nucleus. Show that the average distance is (3/4)a0.

 

 

(b) State and explain the significance of the Variation Principle with an example.

(5+5)

 

  1. (a) Discuss the Pauli Exclusion principle applied to electrons in quantum mechanics.

(b) Explain why when an electron is bound to a system it gives a discrete spectrum while a free particle (as in the case of ionization of atoms) gives a continuous spectrum                                                                                                (7+3)

  1. a) What are the three important approximations that distinguish the HMO method from other LCAO methods.
  2. b) Write down the secular determinant obtained on applying Hückel’s method to the

butadiene molecule and obtain there from expressions for the energy levels. (3+7)

  1. Discuss the Molecular Orbital treatment of H2 molecule and explain how the Valence Bond (Heitler-London) method makes up for what MO theory lacks. (10)

 

  1. Find the number, symmetry species of the infrared and Raman active vibrations of NH3, which belongs to C3V point group. State how many of them are coincident.

(You may, if you wish, use the table of f(R) given below for solving this).

 

Operation:       E     σ       i       C2      C3     C4     C5         C6     S3       S4      S5       S6     S8

              f(R):       3       1    -3      -1       0       1     1.618      2      -2      -1     0.382     0    0.414

 

For any Cn, f(R) = 1 + 2cos(2π/n),            For any Sn, f(R) = -1 + 2cos(2π/n)

 

 

 

D3V      E          2C3      3σv

 

 

A1        1          1         1              z                      x2 +y2, z2

A2        1          1         -1             Rz

E          2          -1         0         (x,y) (Rx,Ry)        (x2-y2,xy) (xz,yz)

 

 

 

 

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Loyola College M.Sc. Chemistry April 2007 Organics Substit.,Addition & Elimination Rxns Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 32

SECOND SEMESTER – APRIL 2007

CH 2808 – ORGANIC SUBSTIT., ADDITION & ELIMINATION RXNS

 

 

 

Date & Time: 17/04/2007 / 1:00 – 4:00 Dept. No.                                      Max. : 100 Marks

 

 

PART – A

Answer ALL questions                                                                       (10 ´ 2 = 20 marks)

 

  1. What are p-complexes in an aromatic electrophilic substitution reaction?
  2. Define partial rate factor and explain.
  3. The rate of acid-catalyzed hydrolysis of benzamide is -0.298 and the relative electron withdrawing effect of -NO2 substituent is + 0.710. Calculate the relative reactivity of  the

nitrobenzamide.

  1. How does nitrous acid react with aromatic 1° and 2° amines?
  2. Explain why iodination of benzene requires HNO3?
  3. Explain Hofmann’s elimination rule with a suitable example.
  4. Among acetic anhydride and n-propyl alcohol, which one is more powerful nucleophile? Justify your answer.
  5. What happens when threo and erythro DL pair of 3-bromo-2-butanol is treated with HBr? Explain.
  6. ‘SN1 rates are greatly increased when there is a double bond in the b-position’. Why?
  7. What happens when isobutyl acetate is strongly heated?

 

 

PART – B

Answer any eight questions                                                          (8 ´ 5 = 40 marks)

 

  1. Explain the effect of electrophile in the reactivity of aromatic substitution reactions.
  2. Describe the various products formed from the reaction of electrophile attacking at the ipso position in nitrobenzene.
  3. Predict the mechanism for the following reaction.

 

 

 

 

  1. Explain neighboring group assistance in free radical reactions.
  2. Explain why in the abstraction step of photochemical chlorination of ethane, ethyl radical formed but not the hydride radical.
  3. Predict the products with mechanism for the following:
    a) Wohl-Ziegler reaction         b) Eglinton reaction
  4. Identify the products obtained when erythro and threo isomers of 1-acetoxy-2-deutero-1,2-diphenylethane is subjected to pyrolysis. Explain.
  5. ‘Acetolysis of both 4-methoxy-1-pentylbrosylate and 5-methoxy-2-pentylbrosylate gave the same mixture of products’. Explain.
  6. ‘Solvolysis of syn-7-p-anisyl-anti-7-norborn-2-enyl p-nitrobenzoate was only 2.5 times faster than that of the saturated compound’. Explain.
  7. ‘Menthyl chloride undergoes dehydrochlorination at a slower rate comparing neomenthyl chloride’. Why?   Identify the products obtained and explain the reaction.
  8. ‘Dehydrohalogenation of 2-fluorohexane mainly gives Hofmann product while
    2-iodohexane gives Zaitsev’s product as major’. Explain.
  9. Explain von-Ritcher rearrangement with mechanism. Give the main evidence for the mechanism.

PART – C

Answer any four questions                                                            (4 ´ 10 = 40 marks)

 

  1. a) Explain the mechanism of bimolecular aliphatic electrophilic substitution with  examples.
  2. b) Describe the effect of solvent on the reactivity of chlorination reaction of  2,3-dimethylbutane.
  3. a) Give the mechanism of sulphonation of benzene. What are the various sulphonating  agents? Give evidences for the mechanism.
  4. b) Give the evidences for the syn, anti, and non stereoselective electrophilic addition of olefins.
  5. Predict the product for the following

 

 

 

 

 

 

 

 

 

 

 

  1. a) How does the presence of a cyclopropyl neighbouring group enhance the rate of     nucleophilic substitution reaction? Explain with two examples.
  2. b) 2-butylacetate on pyrolysis gives a mixture of products with different yields. Why?
  3. a) ‘p-methoxybenzhydryl hydrogen phthalate on solvolysis in methanol results a     racemic ether’. Justify your answer.
  4. b) Explain Bucherer reaction taking b-naphthol as an example.
  5. a) Identify the stereochemistry of the products obtained on the dehydrobromination of        different conformers of 1,2-dibromo-1,2-diphenylpropane.
  6. b) How does selenide elimination help in the synthesis of a,b-unsaturated ketones?

 

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Loyola College M.Sc. Chemistry April 2007 Organic Reaction Mechanism & Stereochemistry Question Paper PDF Download

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     LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 26

FIRST SEMESTER – APRIL 2007

CH 1806 – ORGANIC REACTION MECHANISM & STEREOCHEMISTRY

 

 

 

Date & Time: 27/04/2007 / 1:00 – 4:00         Dept. No.                                                       Max. : 100 Marks

 

 

Part-A

                                                        Answer ALL questions.                     (10 ´ 2 = 20)

  1. Suggest a method of trapping the intermediate of a reaction, using suitable example.
  2. Define microscopic reversibility with example.
  3. What is Arndt-Eistert synthesis?
  4. Predict which of the following products would be got in Baeyer Villiger oxidation of cyclohexylmethyl ketone.Why?
  5. a) What is the catalyst, reactants and the products in Rosenmund reduction reaction?
    b) What is Corey’s reagent and how is it prepared?
  6. Explain axial halo ketone rule with an example.
  7. What is epimerisation? Give an example.
  8. Explain Prelog’s rule with a suitable example.
  9. What are the resolving agents used for the separation of racemic bases? Give the structure of any one.
  10. Explain Cram’s rule with an example

 

PART B

Answer any EIGHT questions                               (8 ´ 5 = 40)

  1. Give the mechanism of Wolf-Kishner reduction reaction.
  2. Predict the product with mechanism.
  3. Predict the product of Fischer-Indol synthesis with sutiable evidence.
  4. What is memory effect? Explain using a suitable example.
  5. What are crossover experiments? How are they helpful in arriving at the mechanism of the reaction?
  6. ‘Iodination of aniline is inversely proportional to the square of the iodide concentration’. Explain using suitable mechanism.
  7. Explain thermal and cationic racemisation with suitable examples.
  8. Explain the conformation of cyclohexane with potential energy diagram.
  9. Explain asymmetric synthesis with suitable examples.
  10. How are optical rotatory dispersion technique helpful in predicting the configuration of molecules?
  11. What atropisomerism?  Explain with a suitable example.
  12. Explain the stereoselective synthesis of reserpine.

PART C

Answer any FOUR questions                  (4 ´ 10 = 40)

  1. a) Predict the product of the reaction of trialkylborane with carbon monoxide in the presence of ethylene glycol, H2O and NaOH.
    b)  Give the mechanism of oxidative decarboxylation.
  2. Give the mechanism of the following rearrangements
    a) Steven’s b) Beckmann’s                        c) Hofmann’s
  3. Explain the following:
    i) Diazotisation of aniline follow third order kinetics.
    ii) The rate law for iodination of acetone depends on the concentration of acetone and the base.  Explain the mechanism using suitable non-kinetic evidence.
  4. a) Explain any two methods of resolution of racemic modifications.
  5. b) What is optical purity? How will you ascertain it?
  6. Assign R or S configuration to the following. Justify your answer
  7. a) Explain the stereochemical synthesis of yohimbine.
  8. b) Write anote on (i) asymmetric destructions (ii) Second order asymmetric transformations.

 

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Loyola College M.Sc. Chemistry April 2007 Organic Chemistry-III Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 40

M.Sc. DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – APRIL 2007

CH 3800 – ORGANIC CHEMISTRY – III

 

 

 

Date & Time: 24/04/2007 / 9:00 – 12:00      Dept. No.                                       Max. : 100 Marks

 

 

PART-A

Answer ALL questions.                                                                       (10 ´ 2 = 20 marks)

  1. Effect the following conversion.

 

  1. State Woodward Hofmann rules for electrocyclization reactions.
  2. Predict the sigmatropic reactions in 1,5-systems with examples.
  3. Define Norrish type II cleavage reactions. Give an example.
  4. What is photosensitization? What is its importance?
  5. ‘Convergent synthesis is a better method in organic synthesis than in stepwise synthesis’. Substantiate this statement with a suitable example.
  6. What are fragmentation reactions? Give an example.
  7. How would you plan the synthesis of 6-methyl-3-octen-2-one by span technique?
  8. What is first generation asymmetric synthesis?
  9. What are the importance of three component system in Clemmensen reduction?

 

 

 

PART-B

Answer any EIGHT questions.                                                           (8 ´ 5 = 40 marks)

  1. Draw the correlation diagram for the electrocyclization of 1,3,5-hexatriene. Predict whether the reaction is feasible thermally or photochemically. (5)
  2. Find out the products with proper stereochemistry in the following reactions.(2´2½)

 

 

 

 

 

  1. Predict the products in the following sigmatropic reactions.

 

 

  1. What are the products formed when 4,4-diphenylcyclohexen-2-one undergoes photochemical rearrangement. Write the mechanism of the reaction.
  2. Illustrate with any two examples, the structure of a molecule in a photochemically excited state.
  3. What is photoisomerisation? Explain with an example.
  4. How would you plan the synthesis of 2-methyl-2-butene by disconnection approach? Explain.
  5. ‘Symmetric target molecules can be planned by disconnection approach symmetrically’.

Explain this with a suitable example.

  1. Explain the role of selectivity and specificity in organic synthesis by taking two examples for each.
  2. How are the following conversions effected?
  3. a) 2,3-dimethylcyclohex-2-en-one ¾¾®  2,2,3,3-tetramethylcyclohexanone
  4. Isopropyl alcohol ¾¾® 1-phenyl-2-methyl-2-propanol
  5. Explain the synthesis of 1,2-difunctionalised compounds with two suitable examples.
  6. Elucidate the structure of reserpine by synthesis.

 

 

PART-C

Answer any FOUR questions.                                                            (4 ´ 10 = 40 marks)

23     a) How cycloaddition reactions are stereoselective? Illustrate with suitable examples.

  1. b) Predict the stereochemistry of electrocyclisation in 4 and 6 electron systems. Give suitable examples.

24     a) Predict the mechanism of following reactions.

 

 

  1. b) Derive the equation for Stern-Volmer expression.

 

 

 

 

 

 

25     a) Explain the Paterno Buchii reactions in alkenes and alkynes with examples.

  1. b) Explain the following photochemical rearrangement reaction.

 

  1. a) Establish the structure of longifolene by synthesis.
  2. b) What are the synthetic importance of Reformatsky reaction? Explain with two suitable examples.

 

  1. a) What are the synthons and synthetic equivalents in the synthesis of phenyl hydroxyl amine and benzanilide?
  2. b) Explain the synthesis of norethisterone.

 

  1. Explain the use of the following in the organic synthesis, with an example each. Explain the mechanism.

 

  1. a) Diels-Alder reaction
    b)            Knoevenagel reaction
    c)            Perkin reaction
    d)            Electroorganic synthesis.

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Loyola College M.Sc. Chemistry April 2007 Organic Chemistry-II Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 31

SECOND SEMESTER – APRIL 2007

CH 2801 – ORGANIC CHEMISTRY – II

 

 

 

Date & Time: 17/04/2007 / 1:00 – 4:00        Dept. No.                                                          Max. : 100 Marks

 

 

PART-A

Answer ALL questions.                                                                       (10 ´ 2 = 20 marks)

  1. Which reagent in the following pair reacts more rapidly with sodium ethoxide in ethanol? Justify your answer.
    Vinyl chloride or allyl chloride
  2. Is the nucleophilic substitution at a vinyl carbon easy? Justify your answer with a suitable example.
  3. Anti-methyl conformation of 2-bromobutane on dehydro bromination gives trans product

while gauche-methyl form gives cis-2-butene as the major product. Why?

  1. What happens when amine oxide such as RCH2CH2N(®O)R2 is heated to 150°C?
  2. Give the structure of the most stable free radical and justify your answer.
  3. What is memory effect? Explain with an example.
  4. Illustrate a free radical rearrangement with an example.
  5. Compare endo and exoenzymes?
  6. Write a short note on denaturation of nucleic acids.
  7. How is the dipeptide, Ala-Gly, synthesized?

 

 

PART-B

Answer any EIGHT questions.                                                           (8 ´ 5 = 40 marks)

  1. ‘For SN1 mechanism, a branching increases the rate of the reaction’. Justify this statement with suitable examples.
  2. Debromination of meso-2,3-dibromobutane mainly gives trans product while
    (±)-isomer gives mainly cis product. Explain.
  3. What happens when 2-methyl-1-propanol is treated successively with CS2/NaOH, CH3I and heated to 200°C? Explain.
  4. ‘Menthyl chloride on dehydrochlorination gives 100% of one isomer while
    neo-menthyl chloride gives 25% of that isomer and 75% 4-methyl isopropyl cyclohexene’. Explain.
  5. The dehydrochlorination in cis and trans 2-chloromaleic acid , the trans isomer reacts about 50 times faster than the cis compound. Explain.
  6. 2-butylacetate when heated to 440°C gives 57% 1-butene, 28% trans 2-butene and
    15% cis 2-butene. Explain.
  7. Explain in detail the mechanism of Benzil-benzilic acid rearrangement.

 

 

 

  1. Predict the product in the following reaction and explain the mechanism.

 

  1. How is a polypeptide or protein synthesized by solid phase method?
  2. Derive Michaelis Menten equation for enzyme action.
  3. Discuss in detail the 2° structure of DNA.
  4. Explain in detail any two methods of N-terminal analysis to predict the primary structure of a protein.

 

PART-C

Answer any FOUR questions.                                                            (4 ´ 10 = 40 marks)

  1. a) On pyrolysis, erythro and threo isomers of 1-acetoxy-2-deutero-1,2-diphenyl    ethane gave in each case trans-stilbene.  Explain.
  2. b) Anti-Markownikov’s rule takes place only for the addition of HBr to an     unsymmetrical alkene and not for any other hydrogen halides. Why? Explain.
  3. a) Elimination of HBr from 2-bromobutane and elimination of trimethylamine from
    2-(N,N-dimethylamino)butane give different products in major amounts. Why?
  4. b) How does the presence of a neighbouring groups enhance the rate of nucleophilic     substitution reaction? Explain with suitable examples.
  5. a) The rates of hydrolysis of alkyl bromides(0.1M) in 0.01M NaOH are in the order

of t-BuBr > MeBr > EtBr > i-PrBr.  Explain.

  1. b) How are the rates of nucleophilic substitution reactions are influenced by      electron withdrawing and electron releasing groups? Explain with examples.
  2. a) Write the mechanism of the following reactions.

 

 

  1. b) Explain the mechanism of following reaarangement reactions.
  2. i) Claisen rearrangement
  3. ii) Baeyer Villiger rearrangement

27     a) Explain with equations the kinetics of competitive inhibition.

  1. b) What are the two methods by which DNA replication takes place?

28     a) Comment on the a-helical structure of proteins.

  1. b) What is meant by immobilization of enzymes? Explain in detail.

 

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Loyola College M.Sc. Chemistry April 2007 Organic Chemistry-I Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 24

FIRST SEMESTER – APRIL 2007

CH 1801 – ORGANIC CHEMISTRY – I

Date & Time: 27/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

PART-A

                                                        Answer ALL questions.                     (10 ´ 2 = 20 marks)

  1. Compare the acid strength of the following. Give suitable explanations.
    p-hydroxybenzoic acid, m-hydroxybenzoic acid and benzoic acid.
  2. Suggest a method of trapping the intermediate of a reaction, using a suitable example.
  3. Define antiaromaticity . Give an example of an antiaromatic compound.
  4. What is solvent isotope effect? How does it affect the rate of the reaction?
  5. How would you prove the formation of benzyne in the ammolysis of chlorobenzene?
  6. Name the electrophile in the nitration of benzene. What are the evidences?
  7. Free radical chlorination of (S)-sec-butylchloride gives 1,2-dichlorobutane as one of the products. Comment on the stereochemistry of the reaction.
  8. Depict the symmetry planes on structures of
    i) dichloromethane and      ii) cis-1, 2-dichlorocyclopropane.
  9. Meso-2, 3-dibromobutane reacts with iodide ion faster than dl-isomer. Why?
  10. State and explain Cram’s rule.
Part-b

                                                        Answer any eight questions.             (8 ´ 5 = 40 marks)

  1. Optically active α – phenylethyl chloride on phenolysis gives an ether with partial retention. Explain the mechanism.
  2. Outline clearly all the possible consequences of ipso attack in the electrophilic substitution of monosubstituted benzene with suitable examples.
  3. Explain cotton effect and predict the cotton effect by the sign of the most occupied octant in

 

  1. Write the most stable conformation for each of the following:
    a) 1,2,2,6,6-pentamethyl-4-hydroxy-4-phenylpiperidine
    b) 2-methyl-5-isopropyplcyclohexanone
    c) 1,3-di-t-butylcyclohexane
  2. Explain the optical isomerism due to restricted rotation with suitable examples.
  3. What is mutarotation? Explain with two examples.
  4. Explain the conformation of cyclohexane with potential energy diagram. What types of strains are associated with rings larger than cyclohexane?
  5. Explain von Richter rearrangement with mechanism.
  6. Explain the linear free energy relationship in aromatic electrophilic substitution reactions.
  7. How would you explain that the rate of base catalysed iodination of aniline in the presence of excess iodide is inversely proportional to the square of the iodide concentration?
  8. ‘In the Fries rearrangement, aryl esters are converted to acyl phenols in the presence of Lewis acids’. How would you show that the reaction is inter or intra molecular?
  9. ‘The acetoylsis of threo-3-phenyl-2-butyltosylate gives the racemic product while the erythro isomer proceeds largely with retention of configuration’. Explain.
Part-C

                                                        Answer any four questions.              (4 ´ 10 = 40 marks)

  1. a) Explain Bucherer reaction with mechanism.
  2. b) Explain the Octant rules in the determination of configuration of molecules.
  3. a) Additon of HBr to 1,3-butadiene is both thermodynamically and kinetically           controlled. Explain using a potential energy diagram.
  4. b) dl-stilbene dichloride undergoes reaction when heated to 200°C with pyridine whereas meso isomer does not.
  5. a) Explain first order asymmetric transformation with a suitable example.
  6. b) Explain epimerisation with suitable examples.
  7. Assign R or S configuration to the following. Justify your answer

 

  1. a) Explain Sommelet-Hauser rearrangement with mechanism.
  2. b) Explain the stereochemistry of the products obtained on heating 3-bromo-2-butanol with HBr.
  3. Explain the following:
    a) Diazotisation of aniline follows third order kinetics.
    b) Aryl halides are less reactive than alkyl halides.
    c) Benzidine rearrangement follows third order kinetics.
    d) Axial haloketone rule.

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Loyola College M.Sc. Chemistry April 2007 Organic Chemical Technology Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 55

FOURTH SEMESTER – APRIL 2007

CH 4955 – ORGANIC CHEMICAL TECHNOLOGY

 

Date & Time: 23/04/2007 / 9:00 – 12:00   Dept. No.                                           Max. : 100 Marks

 

 

 

PART-A

Answer ALL questions.                                                                       (10 ´ 2 = 20 marks)

  1. How is the formation of nitronium ion from nitration mixture detected and confirmed?
  2. How is the DVS ratio of a mixed acid calculated?
  3. Name some of the industrial oxidation reactions with examples.
  4. How are temperature controlled reactions performed industrially?
  5. How is spent acid from nitration reaction recycled?
  6. Define the following
  7. a) potential flow b) flash distillation
  8. What is boiling point diagram?
  9. Draw equilibrium diagram for C6H6-EtOH binary system.
  10. What is glycerin distillation and glycerin vaporization?
  11. What is roughness factor?

 

 

PART-B

Answer any EIGHT questions.                                                           (8 ´ 5 = 40 marks)

  1. Classify various chemical reactors and give a brief account on each.
  2. Write detailed notes on complex series reactions.
  3. Draw Hough nitrator and explain the method of preparation of mononitrobenzene from it.
  4. Give a detailed account on the design and material of reactors used for sulphonation.
  5. How various types of reactors built for halogenation reactions? Explain.
  6. Explain the preparation of a dye industrially?
  7. How will you calculate the vapour composition of a mixture in the distillation process using Raoult’s law?
  8. Discuss about the Hydrostatic equilibrium in a centrifugal field.
  9. Explain the working principle of centrifugal decanter for immiscible liquids.
  10. What are Newtonian and non-Newtonian fluids?
  11. What is Reynolds’s number? How the types flow is observed in Reynolds’s experiment?
  12. What is the pump work in Bernoulli’s equation?

 

 

 

 

PART-C

 

Answer any FOUR questions.                                                            (4 ´ 10 = 40 marks)

 

23     a) Compare batch reactor and longitudinal flow reactor for their performance and types of reactions.

  1. b) What is back mixing? Explain the effect of back mixing in consecutive reactions.

24     a) What are different types of nitrating agents? Explain the mechanism of each reaction.

  1. b) List out various workup procedures to isolate sulphonated products. Explain each one in detail.
  2. With a complete flow chart, explain the industrial preparation of penicillin.
  3. Explain about the total energy of steady flow process.
  4. Write note on types of impellers.
  5. Discuss the mechanical-energy balance in potential flow.

 

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Loyola College M.Sc. Chemistry April 2007 Nuclear & Solid State Chemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 49

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2007

CH 4952 – NUCLEAR & SOLID STATE CHEMISTRY

 

 

Date & Time: 25/04/2007 / 9:00 – 12:00      Dept. No.                                       Max. : 100 Marks

 

 

PART – A

Answer all the questions.                                            (10 x 2 = 20 marks)

  1. Give the unit cell parameters of (a) Monoclinic (b) rhombic systems
  2. What is a photovoltaic cell?
  3. Draw the solid state structures of (a) CdCl2      (b) SiO2
  4. What is a glide plane?
  5. Li+ doped in NiO is a good conductor. Explain.
  6. What are isotones? Give one example.
  7. What is the mechanism of g-ray emission?
  8. Define a Curie. How is it derived?
  9. Mention the principle involved in Geiger-Muller (GM) counter.
  10. State the nuclear spin of (a)       (b)

PART  – B                   (8 x 5 = 40 marks)

 

Answer any EIGHT questions.

  1. Write a note on Bravais lattices.
  2. Explain the “screw axis” and the operation involved.
  3. Write a note on photogalvanic cells.
  4. What are organic semiconductors? Explain their advantages.
  5. What are tungsten bronzes? Explain their properties.
  6. Discuss the inclusion compounds formed by graphite and their conducting
    characteristics.
  7. Write a note on scintillation counters.
  8. Discuss the principle and the construction of cyclotron.
  9. Write a note on chemical dosimeters.
  10. Describe the use of radioisotopes in medicine.
  11. Give the merits of the nuclear shell model of the nucleus.

 

PART – C                   (4 x 10 = 40 marks)

 

Answer any FOUR questions.

 

  1. Discuss the behaviour of high temperature superconductors. Explain the
    Bardeen-Cooper-Schriefer (BCS) theory.
  2. Describe the photoelectrocatalysis in splitting of water using TiO2 and SrTiO3.
  3. Explain the “atomic scattering factor” and “structure factor” in deriving the
    electron density by Fourier transform method.
  4. Derive the expression for binding energy of the nucleus using liquid drop model.
  5. Discuss the mechanism of a-ray emission from the nucleus.
  6. Discuss the fission yield curve. Discuss the energy involved and mechanism of
    nuclear fission.

 

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Loyola College M.Sc. Chemistry April 2007 Molecular Spectroscopy Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 37

SECOND SEMESTER – APRIL 2007

CH 2950/CH 2802 – MOLECULAR SPECTROSCOPY

 

 

 

Date & Time: 19/04/2007 / 1:00 – 4:00     Dept. No.                                                             Max. : 100 Marks

 

 

Part-A   ANSWER ALL QUESTIONS (10 x 2 = 20)

 

  1. Give the range of frequency values of (a) C=O (b) C-H (c) N-H   (d) O-H
  2. Mention the standard used in EPR. Draw its structure.
  3. A compound C6H12 has a single singlet signal in its 1H NMR spectrum. Identify the structure.
  4. Mention the high intense mass spectral peaks in (a) C6H5CH3 (b) CH3CHO
  5. Mention the possible electronic transitions in (a) C6H5COCH3   (b) C6H6
  6. Identify the point groups for the following molecules:
  • NH3 (b) CCl4               (c) Cl2          (d) C6H6
  1. Identify which of the following molecules will give both rotational and IR
  • Cl2 (b) CH4  (c) CH3Br   (d) H2O
  1. What is the difference between a fundamental and a hot band?
  2. What is unique about C1 point group? Give an example.
  3. Explain the meaning of the letters A and u in the irreducible representation Au of the character table.

Part-B   ANSWER ANY EIGHT QUESTIONS (8 x 5 = 40)

  1. How are the charge-transfer compounds studied by UV-Visible spectral studies?
  2. What is nuclear overhauser effect (NOE)? Explain with one example.
  3. How are infrared spectral studies useful in the study of hydrogen bonding?
  4. What are isotopic peaks and meta-stable peaks? Explain with one example.
  5. Sketch the EPR spectrum of C6H50 (phenyl radical) and explain.
  6. Sketch and explain the Mossbauer spectra of [Fe(CN)6]4- and [Fe(CN)6]3-.
  7. Explain how P, Q, and R branches of absorption bands are obtained in vibration-rotation spectra of molecules?
  8. What are stokes and anti-stokes lines? Compare their intensities in the Raman vibrational spectrum of a compound.
  9. The fundamental and first overtone transitions of CO are centred at 2143.26 cm-1 and 4260.04 cm-1 respectively. Evaluate the equilibrium vibration frequency and the zero-point energy.

 

 

 

 

  1. (a) What is similarity transformation?

(b)When do we say two symmetry operations are in the same class? Illustrate with a suitable

example.                                                                                                            (2+3)

  1. (a) Explain ‘Fermi Resonance’ with a suitable example.

(b) If a spectral line has a natural line width of 0.17 cm-1, what is the life-time of the excited

species?                                                                                                              (3+2)

  1. Reduce the following reducible representation

Td    E       8C3        3C2        6S4         6σd

4     1         0         0         2

 

into irreducible representation using the reduction formula and the Td character  table given

below:

 

 

Td          E          8C3      3C2      6S4       6σd

 

 

A1        1          1          1         1         1                                 x2+y2+z2

A2        1          1          1         -1         -1

E          2          -1         2         0         0                                 (2z2-x2-y2, x2-y2)

T1         3          0          -1         1         -1         (Rx,Ry,Rz)

T2         3          0          -1         -1         1         (x,y,z)              (xy,xz,yz)

 

 

Part-C   ANSWER ANY FOUR QUESTIONS (4 x 10 = 40)

 

  1. Discuss the principle and instrumentation involved in 1H NMR.
  2. Discuss the Woodward-Hoffmann’s rules for conjugated dienes and α, β–unsaturated ketones.
  3. Write a note on

(a) McLafferty Rearrangement

(b) Influence of the solvent λmax in the UV-Visible spectral studies.

  1. (a) State and explain Franck-Condon Principle. How are intensity variations of electronic spectra explained by this principle?

(b) Assume the following data for the molecule 1H19F. Bond length = 91.68 pm, Bond force constant = 965.7 Nm-1, Atomic masses: 1H = 1.66 x 10-27 kg, 19F = 31.55 x 10-27 kg. Calculate the zero-point energy, the energy of the fundamental vibration ν0, the rotational constant B, and the wave numbers of the lines P1 and R0.                                                                 (5+5)

 

  1. (a) Outline the causes for the broadening of spectral lines.

(b)  What is transition dipole moment? How does it determine whether a transition between two energy levels is allowed or forbidden?                                      (6+4)

 

 

 

  1. Find the number, symmetry species of the infrared and Raman active vibrations of NH3, which belongs to C3V point group. State how many of them are coincident.

(You may, if you wish, use the table of f(R) given below for solving this).

 

Operation:      E     σ       i       C2      C3     C4     C5         C6     S3     S4       S5       S6         S8

              f(R):       3       1    -3      -1       0       1     1.618      2      -2      -1     0.382     0       0.414

 

For any Cn, f(R) = 1 + 2cos(2π/n),            For any Sn, f(R) = -1 + 2cos(2π/n)

 

 

D3V     E       2C3     3σv

 

A1    1       1         1              z                      x2 +y2, z2

A2     1       1         -1             Rz

E       2       -1         0         (x,y) (Rx,Ry)        (x2-y2,xy) (xz,yz)

 

 

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Loyola College M.Sc. Chemistry April 2007 Instrumental Methods Of Chemical Analysis Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 36

M.Sc. DEGREE EXAMINATION – ZOOLOGY / BMIS

SECOND SEMESTER – APRIL 2007

CH 2901 – INSTRUMENTAL METHODS OF CHEMICAL ANALYSIS

 

 

 

 

Date & Time: 26/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

Part-A   ANSWER ALL QUESTIONS (10 x 2 = 20)

 

  1. Define: (i) molarity (ii) ppm
  2. Explain Bathochromic shift with an example.
  3. What is the volume of 6M H2SO4 (MW=98 gmol-1) that contains 20 g of H2SO4 solute?
  4. What are the two sources of flames used commonly in Atomic Absorption Spectrometers?
  5. Define the specific rotation of an optically active compound.
  6. Determine the pH of 10-3M Ba(OH)2
  7. Compare the fundamental vibrational frequency of C-O and C=O.
  8. How is the internuclear distance determined by X-ray diffraction studies?
  9. Which of the following will give NMR signal (i) 8O16 and (ii) 6C13
  10. Predict the m/e value for the molecular ion peak of C6H6.

 

 

Part-B   ANSWER ANY FIVE QUESTIONS (5 x8 = 40)

 

  1. (a) State Beer-Lambert’s law and explain under what conditions it is not applicable.

(b) With a schematic diagram indicate the different parts and working of a Double-Beam Spectrophotometer. What are its advantages?                                      (3+5)

  1. With a sketch discuss the principle, parts and working of a fluorimeter and how it is used in the analysis of riboflavin (vitamin B2).
  1. With a diagram outline the principle, parts and working of a cold-vapor atomic absorption spectrometer in the determination of mercury in a given biological sample?
  1. With a schematic diagram discuss the principle, parts and working of a spectropolarimeter. Mention any one application.
  2. How is the fluoride content in water sample estimated using ion selective electrode?
  3. Describe the principle and instrumentation of NMR spectroscopy.
  4. Write an account of ‘Isotopic dilution analysis’.
  5. Calculate the fundamental frequency in the infrared absorption region for the C=C stretching vibration. (k = 9.77 x 105 dynes cm-1; c = 3 x 1010 cms-1)

 

 

 

Part-C   ANSWER ANY TWO QUESTIONS (2 x20 = 40)

 

  1. (a) Discuss in detail the instrumentation and application of nephelometry

 

(b) Discuss the principle and working of an Atomic Absorption Spectrometer

and how it can be used in the quantitative determination of lead (Pb2+) in blood.

(10+10)

  1. Define and explain briefly the following concepts and its importance with a

suitable example:

 

(a) Difference Spectrometry (b) turbidimetry (c) ICP AES   (d) monochromator

(e) hollow-cathode lamp                                                                    (4 each)

 

  1. (a) Discuss the principle and instrumentation of HPLC.

(b) Describe the applications of neutron diffraction.

 

  1. (a) Give an account of the application of IR spectroscopy.

(b) Distinguish the following

H    H                                            H           H

|      |                                              |             |

(i)    H –C—C—O—H           and       H—C—O—C—H    using NMR.

|      |                                              |             |

H    H                                            H           H

H

|

(ii)   CH3 –C—H           and           CH3 –C–OH             using IR

||                                            |

O                                           H

 

 

(iii)   CH3OH                 and          CH3–CH2–OH         using mass spectra.

 

 

 

 

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Loyola College M.Sc. Chemistry April 2007 Instrumental Analysis Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 48

M.Sc. DEGREE EXAMINATION – PHYSICS

THIRD SEMESTER – APRIL 2007

CH 3900 – INSTRUMENTAL ANALYSIS (FOR PHYSICS)

 

Date & Time: 27/04/2007 / 9:00 – 12:00      Dept. No.                                       Max. : 100 Marks

 

 

 

PART – A

 

Answer ALL the questions                                                              (10 x 2 = 20 marks)

 

  1. How many molar Ca+2 is 100 ppm of Ca?
  2. Mention the mobile and immobile phase in TLC.
  3. Determine the pH of 10-2M Ba(OH)2 .
  4. What is diverse ion effect?
  5. Mention the steps involved in crystallization.
  6. What are the factors which influence termogram?
  7. What is nernst glower?
  8. Define molar absorptivity.
  9. Name few metals which can be analysed by flame photometry.
  10. Define Rf Mention the factors which influence Rf Value.

 

PART – B

 

Answer any EIGHT questions                                                           (8 x 5 = 40 marks)

 

  1. Determine the solubility of BaSO4 in 0.1 m Na2SO4. KSP of BaSO4 is 1 x 10-10 mol2 dm-6.
  2. Will the pH of water be affected by temperature?
  3. How is the solubility of a sparingly soluble substance determined using conductometer?
  4. Compare GLC and HPLC.
  5. Explain Soxhlet extraction.
  6. How is exactly 0.1 N HCl prepared?
  7. Write a note on crystallization.
  8. How is a mixture of halides separated by ion exchange chromatography?
  9. Determine the pH of a buffer solution containing 10-2 m NH4Cl and 10-1m NH4 Kb of NH4OH is 10-5.
  10. Distinguish primary and secondary standards with example.
  11. Explain partition chromatography.
  12. 10g NaOH is dissolved in 1 litre water. Calculate the concentration in (i) % by weight  (ii) molarity   (iii) ppm.

 

PART – C

 

 

 

Answer any FOUR questions                                                          (4 x 10 = 40 marks)

 

  1. Describe the instrumentation of Gas chromatography.
  2. How is the pH of a solution determined by using a potentiometer?
  3. How is a mixture of amino acids separated by paper chromatography?
  4. Draw the thermogram of CaC2O4.H2O(s) and explain.
  5. Derive Beer Lambert’s law. How is it verified?  What are its limitations?
  6. a) Discuss the principle of flame photometry.
  7. b) Differentiate AAS from flame photometer.

 

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Loyola College M.Sc. Chemistry April 2007 Heterocyclic & Natural Products Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 51

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2007

CH 4954 / 4951 – HETEROCYCLIC & NATURAL PRODUCTS

Date & Time: 27/04/2007 / 9:00 – 12:00      Dept. No.                                                Max. : 100 Marks

 

 

PART – A

Answer ALL questions                       (10 ´ 2 = 20 marks)

  1. How would you convert 1,1,3,3- tetraethoxy propane into pyrazole?
  2. How would you synthesis antipyrine from ethyl acetoacetate?
  3. How would you prepare uracil from urea?
  4. Explain Hoffmann exhaustive methylation method with an example.
  5. What are the uses of atropine?
  6. How would you confirm the presence of methylenedioxy group in peepuloidin?
  7. What happens when cadenine is treated with sulphur?
  8. Give the stereo chemical structure of Gibberellic acid.
  9. What are the different ring systems present in the cholesterol?
  10. How would you prove the presence of ketonic group in cortisone?

 

PART – B

Answer any EIGHT questions                (8 ´ 5 = 40 marks)

  1. How would you prepare alloxan from barbituric acid?
  2. How would you prepare flavones by Baker-Venkataraman synthesis?
  3. How would you effect the following conversion?

Coumarin      ¾¾¾¾®   anthocyanadin

  1. What happens when imadazone is treated with
    a) PhCOCl, NaOH      and        b) H2O2
  2. Explain Willstatter synthesis of tropine.
  3. Establish the structure of heptaphylline with synthesis.
  4. Explain the synthesis of papaverine.
  5. Explain the Nametkin rearrangement with a suitable example.
  6. Give the structure of Vitamin-A. How would you establish its structure by synthesis?
  7. Explain the synthesis of oestrone.
  8. What are the different molecular rearrangements involved in steroids? Explain any one with
    a suitable example.
  9. Explain the ring junction stereochemistry in steroids with suitable examples.

PART – C

Answer any FOUR questions                 (4 ´ 10 = 40 marks)

  1. a) How would you obtain uric acid from urea?
    b) Establish the structure of belladine.
  2. a) Explain the electrophilic substitution reactions in xanthione.
  3. b) Establish the structure of cocaine by synthesis.
  4. a) Explain the ring cleavage reactions in uric acid.
    b) Establish the structure of abietic acid.
    26.       Explain all steps involved in the total synthesis of cholestrol.
  5. How would you synthesis cortisone from 3-methyl penta-1,3- diene? Explain the steps with mechanism.
  6. Establish the structure of camphor with synthesis.

 

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Loyola College M.Sc. Chemistry April 2007 Electrochemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 52

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2007

CH 4805 / CH 4808 – ELECTROCHEMISTRY

 

 

 

Date & Time: 18/04/2007 / 9:00 – 12:00          Dept. No.                                                          Max. : 100 Marks

 

 

PART – A

 

Answer ALL the questions                                                                (10 x 2 = 20 marks)

 

  1. The deviation from Debye Huckel Onsager equation is more marked as the atomic weight of alkali metal halide increases – Explain.
  2. Which of the following will have greater ion – ion interaction?

(i) 0.01 m KCl             (ii) 0.01 m CuSO4.

  1. and  are 0.337 and 0.521V respectively. Is it easier to

oxidize  cu to cu+ or cu to cu+2?

  1. According to Stern’s model, how do ions congregate in solution?
  2. Define potential of zero charge.
  3. Derive the expression for the electrochemical reaction rate on the basis of Faraday’s laws of electrolysis.
  4. Define exchange current density of and electrode.  How is it related to its polarisability?
  5. Indicate the potential range at which an electrode shows ohmic and non ohmic behaviours.
  6. Define transfer coefficient.  How can it be determined experimentally?
  7. Define diffusion over potential.  Explain how the concentration over potential can arise mainly due to diffusion.

 

PART – B

 

Answer any EIGHT questions                                                           (8 x 5 = 40 marks)

 

  1. Consider the cell, cd/cdcl2 . 2½ H2O/Agcl(s)/Ag(s).  The emf of the cell at 15C is 0.67531and the temperature coefficient of emf is –0.00065 Vdeg-1.  Calculate DG, DS   and DH for the above cell reaction at 15oC.
  2. Derive an expression for the Debye Huckel length.
  3. Determine the solubility of BaSO4 in (i) 0.1m BaCl2 and (ii) 0.1m KNO3. Ksp of BaSO4 is 1 x 10-10 mol2 dm-6.
  4. Calculate the limiting molar conductance of lanthanum sulphate from the following data:
  1. What are electro capillary curves?  How is it influenced by surfactants?  Explain.
  2. Write notes on electro-osmosis.
  3. The exchange current density, Io of a certain electrode and its symmetry factor, b are 1.35 mA and 0.45.  Calculate is cathodic current at an over potential of 300mV.
  4. Calculate the magnitude of the anodic Tafel slope of the plot of logi vs h for an electrode having its anodic transfer coefficient 1.5 at 298K.
  5. Calculate the minimum potential required for the discharge of Ag+ from its 1x 103 M solution at 298K (The SRP of Ag+/Ag system = 0.80V).
  6. The reduction of Fe2+ to Fe follows the following mechanism

Fe2+ + H2O ⇄ FeOH+ + H+      eq conts K1 ….. (1)

FeOH + e ⇄ FeOH                eq conts K2 ….. (2)

FeOH +H+ + e ⇄ Fe + H2O      eq conts K3 ….. (3)

Determine the following parameters if step-2 is rds.

= ;       ;   n     ;  r  ;   and

  1. Discuss any five types over potential for an electrode system.
  2. State the following relation for polarography connecting
  • EMF & current density
  • Current density & concentration

Explain their applications.

PART – C

Answer any FOUR questions                                                            (4 x 10 = 40 marks)

  1. Derive Debye Huckel Onsager equation.  How is it verified?
  2. Give an account of ‘Parallel Plate Consdensor Model’ to explain the double layer structure.
  3. Define ion-ion interaction.  Derive an expression for ion-ion interaction interms of chemical potential.
  4. a) Derive the Butler-volrmer equation relating current and over potential for a

simple  electrode system.

  1. b) Deduce Ohm’s law equation from the above relation.
  1. a) Explain the factor deciding electrode rectification?
  1. b) Discuss Butler-Volmer equation for different value of over potential.
  1. The electrochemical reduction of I to I proceeds by a three step mechanism viz., fast equilibrium dissociation of (i) I to I2 & I (ii) I2 to I (iii) followed by the slow reduction of the dissociated I atoms to I.  Write the mechanism of the reaction and hence determine the transfer coefficient for the reaction.

 

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Loyola College M.Sc. Chemistry April 2007 Coordination Chemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 42

M.Sc. DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – APRIL 2007

CH 3802 – COORDINATION CHEMISTRY

 

 

 

Date & Time: 28/04/2007 / 9:00 – 12:00      Dept. No.                                       Max. : 100 Marks

 

Part – A

Answer all the questions                                                                  (10 x 2 = 20)

 

  1. What are inert and labile complexes?
  2. What is chelate effect? Explain with an example.
  3. What is the ground term of a free ion with 3d9 configuration?
  4. What are π-acceptor ligands? Give two examples.
  5. Explain Why do the bond order values of C-O in mixed phosphine carbonyls vary in the order [(Ph3P)3Mo(CO)3] < [(Cl3P)3Mo(CO)3].
  6. Why are the magnetic moment of Co(II), high spin, octahedral complexes much higher than that of tetrahedral complexes?
  7. Explain SN1CB mechanism with an example.
  8. Why is MnO4– ion, a d0 system coloured?
  9. What is meant by hapticity of a ligand? How is it designated?
  10. Differentiate the types of cytochromes.

 

Part – B

Answer any eight  questions                                                          (8 x 5 = 40)

 

  1. Explain the geometry of [Fe(H2O)6]2+ and [Fe(CN)6]4- ions using VB theory.
  2. How does M.O theory explain the field strength of Cl– and CN–.
  3. State and explain Jahn-teller theorem. Discuss the consequences of Jahn-Teller distortions on the electronic spectra of octahedral complexes.
  4. How is optical rotatory dispersion study useful to determine the absolute configuration of chiral complexes.
  5. Explain the EPR spectral features of CuII(salen) complex.
  6. What is trans effect? Discuss the theories of trans effect.
  7. Explain the types of  photosubstitution reactions of metal complex with examples.
  8. Explain the fluxional isomerism with two examples.
  9. Explain the synergic effect of metal-ligand bonding in metal carbonyls.
  10. Why is the electron transfer in the system [Co(NH3)6]2+ –  [Co(NH3)6]3+  slower than that in the system [Fe(CN)6]4- and [Fe(CN)6]3- .
  11. Predict the structure of the following using Wade’s Rule. a) Os5(CO)16  b)Re4(CO)162-.
  12. Describe the essential structure of haemoglobin and explain the cooperativity in its oxygenation.

 

 

 

Part – C

Answer any four questions.                                                                    (4 x 10 = 40)

 

  1.  Explain the splitting of degeneracy of d-orbitals in square planar environments of ligands.
  2.  Discuss the bonding in ferrocene on the basis of molecular orbital energy level diagram.
  3.  Explain the features of Tanabe- Sugano and Orgel diagrams. Construct Orgel diagram for d3and d7, tetrahedral and octahedral complexes.
  4. a) Explain the principles involved in the Mossbauer spectral analysis of metal complexes.
  1. b) How do the Mossbauer spectra of K4[Fe(CN)6] and K3[Fe(CN)6] differ.
  1. Discuss in detail the mechanisms of outer and inner sphere electron transfer in metal complexes.
  2.  Write short notes on
  1. a) Wilkinson catalyst b) Zeigler-Natta catalyst
  2. c) Wacker’s process d) Fischer Tropsch process

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Loyola College M.Sc. Chemistry April 2007 Chemistry Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

«degree» DEGREE EXAMINATION – CHEMISTRY

«semester» SEMESTER – APRIL 2007

CH 3805-   CHEMISTRY

 

 

 

Date & Time: «date» / «time»      Dept. No.                                       Max. : 100 Marks

 

 

PART – A

Answer ALL the questions.                                        (10 ´ 2 = 20 marks)

 

  1. Define confidence interval.
  2. 200 g sample of a well water is found to contain 0.1132 g calcium oxide. Determine the concentration of calcium in well water in ppm.
  3. What is the gravimetric factor for Fe+3, when it is precipitated as ferric hydroxide and weighed as ferric oxide.
  4. Explain ‘replacement titration’ with an example.
  5. Predict the equivalence point potential for the system: B+  vs  A+4

 

A+4 + 2e–  ⇌  A+

 

B+4 + 3e–    ⇌  B+

 

  1. Distinguish coulometry and voltametry.
  2. What is residual current? What is it due to?
  3. Mention two applications of DTA.
  4. Explain the effect of pH on electrode deposition.
  5. How is K+ ion in serum determined?

 

PART – B

Answer any EIGHT questions.                                   (8 ´ 5 = 40 marks)

 

  1. Show that equivalence point potential is pH dependent for the titration of Fe+2 vs MnO4–  in acidic medium.
  2. What is diverse ion effect? How is it explained?
  3. Prove that the conditional formation constant in EDTA titrations is pH dependent.
  4. Discuss the salient features of acid base titration in non-aqueous solvents.
  5. Describe the factors which influence Dpm/DV in complexometry.
  6. Draw the titration curve for the titration of 20.00mL of 0.1000 M CH3COOH  vs  0500 M NaOH Ka of CH3COOH is 10-5.
  7. Draw a typical cyclic voltagram and indicate Ip(a), Ip(c),  Ep(a) and Ep(c) on the diagram.
  8. Explain how polarographic method can be used in quantitative studies.
  9. Briefly explain:

(i)  Flame photometry             (ii) Atomic absorption spectroscopy

  1. Write notes on neutron activation analysis.
  2. How is Fe+3 determined by spectrophotocolorimetric method?
  3. 00 g of p-nitroaniline in 100 mL of 0.1 N HCl solution shows an absobance of 0.825 at its lmax when measured in a cell with 1.0 cm thickness. An unknown sample of the same compound in the 0.1 N HCl solution in the same cell shows an absorbance of 0.500. Calculate the amount of p-nitroaniline in solution in g/Litre.

 

 

 

 

 

 

 

 

 

 

PART – C

Answer any FOUR questions.                                                (4 ´ 10 = 40 marks)

 

  1. A common method to determine phosphorus in urine is to treat the sample after removing the protein, with molybdenum(VI) and then reduce the resulting 12-Molybdophosphate complex with ascorbic acid to give an intense blue coloured species called Molybdenum blue.  The absorbance of Molybdenum blue can be measured at 650 nm.  A patient produced 1122 mL of urine in 24 hours.  A 1.00 mL aliquot of the sample was treated with Mo(VI) and ascorbic acid and was diluted to a volume 50.00 mL.  A calibration curve was prepared by treating 1.00 mL aliquots of phosphate standard solutions in the same manner as the urine sample.  The absorbances of the standards and the urine sample were obtained at 650 nm and the following results were obtained
Solution ppm of P Absornace at 650 nm
1.00

2.00

3.00

4.00

Urine sample

 0.230

0.436

0.638

0.848

0.518

Apply the method of least squares to find the slope, intercept and the standard deviation of the result.  Determine the concentration of P in ppm in the urine sample.

  1. 4800 g sample that contains KCl and KI gave a precipitate of 0.2720 g silver halide. A 0.7200 g sample of the same material is titrated with    0.1020 M AgNO3 requiring 25.80 mL.  Calculate the percentage of KCl and KI in the sample.
  2. Discuss the principle and instrumentation of TGA.
  3. (a) Draw a neat polarogram and explain the features.

(b) Write a note on chemiluminescence.

  1. Differentiate the following:

(a) Phosphorescence and fluorescence

(b) TGA and DTA

  1. A 0.3284 g sample of brass (containing Pb, Zn, Cu, Sn) was dissolved in HNO3. The sparingly soluble SnO2.4H2O was removed by filtration and the combined filtrate and washings were then diluted to 500.00 mL.  A 10.00 mL aliquot was suitably buffered; titration of the Pb, Zn, Cu in this aliquot required 37.56 mL of 0.002500 M EDTA.  The copper in a 25.00 mL aliquot was masked with thiosulphate; the Pb and Zn were then titrated with 27.60 mL of the EDTA solution.  Cyanide ion was used to mask the Cu and Zn in  00 mL aliquot; 10.80 mL of the EDTA solution was needed to titrate the Pb ion.   Determine the composition of the brass sample; Evaluate the percentage of tin by difference.

 

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Loyola College M.Sc. Chemistry April 2007 Chemistry Of Main Group Elements Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 33

SECOND SEMESTER – APRIL 2007

CH 2809 – CHEMISTRY OF MAIN GROUP ELEMENTS

 

 

 

Date & Time: 19/04/2007 / 1:00 – 4:00   Dept. No.                                                          Max. : 100 Marks

 

 

Part-A

Answer all questions. Each question carries two marks 

  1. List some differences between chemical properties of main group elements and sub-group elements.

 

  1. Why do some ionic compounds like BaSO4 have poor solubility in water?
  2. How is VSEPR model different from VBT?
  3. Explain LCAO.
  4. How does the geometry of a molecule influence its stability?
  5. Illustrate anti Markownickoff addition of BH2 during hydroboration.
  6. What are silyl amines? How are they prepared?
  7. Differentiate metalloboranes and metallocarboranes.
  8. Illustrate the contrasting tendency of benzene and borazine toward addition reactions.

 

  1. What are cyclic phosphazane? Give the synthesis of one such compound.

 

Part-B

Answer Eight questions. Each question carries five marks 

  1. What are the differences in the properties of E-Cl bond in CCl4 and PbCl4? Give reasons.

 

  1. Give the significance of electronegativity and electronegativity difference citing examples.

 

  1. Explain characteristic reactions of (i) electron-rich and (ii) electron-deficient molecules.

 

  1. Give a brief account of interhalogen compounds.

 

  1. Why does Xe alone form compounds among noble gases? Why does it combine only with some halogens and oxygen?

 

  1. Why is SO2 a good oxidizing agent while SeO2 and TeO2 are not?

 

  1. Give an account of the synthesis and structural aspects of isopoly molybdates and tungstates.

 

  1. Explain the method of synthesizing two-cage phosphorous sulfides.

 

 

 

 

 

  1. What are cyclic metaphosphates? Give an account of their synthesis and structural aspects.

 

  1. Write a note on linear polyphosphazenes.

 

  1. Explain the utility of organochlorides of nonmetals for catenation by coupling.

 

  1. Cite an account of the synthesis of two homocyclic inorganic rings.

 

Part-C

Answer Four  questions. Each question carries ten marks 

  1. Draw MO energy level diagram for (i) a highly ionic and (ii) a highly covalent diatomic molecules and explain the nature of bonding and anti-bonding orbitals.

 

  1. Discuss the unique chemical properties of boron and nitrogen group elements and their compounds.

 

  1. Discuss allotropes of carbon and their properties.

 

  1. Explain the solvolysis reactions of nonmetal halides and organohydrides.

 

  1. Give a brief account of the preparation of polyhedral borane anions. Explain the structure and bonding in these compounds with the help of PSEPT.

 

  1. (a) Give an account of the formation and structural aspects of heteropoly anions.

(b) Give an account of the reactivity and utility of non-metal fluorides as

fluorinating agents.

 

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Loyola College M.Sc. Chemistry April 2007 Chemistry Of Heterocyclics & Natural Products Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 38

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2007

                         CH 2951 – CHEMISTRY OF HETEROCYCLICS AND NATURAL PRODUCTS

 

 

 

Date & Time: 24/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

PART-A

 

Answer all the questions                                                 (10 x 2 = 20)

 

  1. What are terpenoids? Give an example.
  2. What are isoprene and special isoprene rule? How are they useful in predicting the structure of cadienine?
  3. What is the end product of Hoffmann degradation of N-methylpiperidine?
  4. Why pyridine is less reactive than benzene towards eletrophiles?
  5. Give the structures of the products in the following reactions:
  6. a) quinoline KMnO4
  7. b) isoquinoline      KMnO4
  8. What are ureides and purines? How are they related?
  9. Mention any two qualitative test for cholesterol.
  10. What are harmones?
  11. What are iodine value and polenski value?
  12. Give the structure of atropine

 

PART – B

Answer any Eight questions                                     (8 x 5 = 40)

 

  1. Explain a) Fischer Indole synthesis b) Skraups’ synthesis of quinoline.
  2. Complete the following reactions:

Imidazole + 2 C6H5COCl + 3NaOH

Imidazole + H2O2

  1. What are the different products formed from the ozonolysis reaction of squalene? Give the molecular structure also.
  2. How will you prove morphine contains phenanthrene ring?
  3. How is tropine converted to 2-ethylpyridine?
  4. Explain the reaction and the products formed by the action of dilute and concentrated KMnO4 of papaverine.

 

  1. Explain the Robinson method of synthesizing anthocyanidine.
  2. Explain the synthesis of flavone from alkylated salicylic acid and acetophenone.
  3. Explain the structural relationship between flavonols(quercetin) and anthocyanidine(cyanidine chloride)
  4. Write the structural formula of pyrimidine. How is it obtained from barbituric acid.
  5. Write short notes on a) Riemer-Tiemann reaction b) Mannich reaction of pyrrole
  6. How is camphoric acid synthesized from 3,3-dimethylglutaric ester?

 

PART-C

Answer any four the questions                                  (4 x 10= 40)

 

  1. Compare the reactivity of furan, thiophene and pyrrole in electrophilic substitution reactions.
  2. a)Account for the fact that pyridine undergoes electrophilic substitution at the β-position. b)Write notes on Hantzsch synthesis of pyridine and Knorr synthesis of pyrrole.
  3. Explain the structural elucidation of cyanidine chloride.
  4. How is the structure of tropine established?
  5. Discuss the structural elucidation of morphine.
  6. How is the structure of Gibberilic acid established?

 

 

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Loyola College M.Sc. Chemistry April 2007 Chemical Kinetics Question Paper PDF Download

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 41

M.Sc. DEGREE EXAMINATION – CHEMISTRY

THIRD SEMESTER – APRIL 2007

CH 3801 – CHEMICAL KINETICS

 

 

 

Date & Time: 26/04/2007 / 9:00 – 12:00      Dept. No.                                       Max. : 100 Marks

 

 

Part A

Answer ALL the questions.                                                    (10 x 2 = 20 Marks)

  1. Differentiate between time order from true order.
  2. At 518 K, the half life for the decomposition of a gaseous compound initially at 363 torr

was 410 s.  When the pressure was 169 torr, the half life was 880 s.

Determine the order of the reaction.

  1. The rate constant for the reaction of the type A2- + B– à X3- + Y is 0.2 M-1 min-1 in zero ionic strength. Calculate the rate constant of the above reaction in water at 250C in an ionic strength of 0.5 M.
  2. What is the significance of electrostriction?
  3. Write down the expression for the rate constant of a reaction between two linear molecules forming a linear transition state on the basis of ARRT.
  4. What is meant by ‘turnover number’?
  5. For the reaction between 2NO(g) + O2(g) à 2 NO2(g), the observed rate decreases with increase in temperature.
  6. What is meant “capillary condensation” ?
  7. Calculate the Hammett acidity function (H0) if pKBH+ for the base 4 Chloro 2 nitro

aniline (B) is –3.3 and [BH+]/[B] = 8 x 10-4

  1. Mention the steps involved in a chain reaction with an example.

PART – B

Answer ANY EIGHT questions                                            (8 x 5 = 40 Marks)

  1. Describe the potential energy surface of the following reaction. HAHB + HC <=>  HBHC + HA.
  2. The rate constant for the decomposition of a certain substance is 1.7 x 10-2 dm3 mol-1 s-1 at 240C and 2.01 x 10-2 at 370 Evaluate the activation energy of the reaction.
  3. Calculate the number of collisions per s between oxygen molecules in 1 cm3 at a total pressure of 1 atm and at a temperature of 270 The molecular radius oxygen is 1.46×10-8 cm.
  4. Explain the kinetics of unimolecular reactions using Lindemann’s Theory.
  5. Explain the significance of volume of activation for reactions in solution phase.
  6. The pre-exponential factor for a certain first order reaction is 3.98 x1013 s-1 and Ea = 180 KJ mol-1. Calculate DH#, DS# and DG# for the reaction at 2000C (R=8.314 J K-1 mol-1)
  7. Differentiate van’t Hoff intermediates from Arrhenius intermediates.
  8. Write BET equation. Mention the terms involved.  How is it verified?
  9. How is Stern-Volmer constant evaluated?
  10. For the following parallel first order reaction, the percentage yields of he two products B and C are 1.2 and 98.8 respectively.  The overall half life is 21.8 y.  Calculate he rate constant for each of the two parallel paths.                                                 B

A

C

  1. Outline the various steps involved in the thermal decomposition of acetaldehyde.
  2. Discuss the principle of flash photolysis.

PART – C

Answer ANY FOUR questions                                              (4 x 10 = 40 Marks)

  1. Compare the rate constants calculated by the ARRT and the Collision Theory for the reaction between two atoms. Explain.
  2. Using double sphere model for a reaction between two ions deduce the relation connecting the rate constant and dielectric constant of the medium and explain.
  3. Explain an two of the following a) Relaxation methods b) Skrabal plots  c) kinetics of explosions
    1. Explain Michaelis-Menton kinetic scheme for an enzymatic reaction. Deduce the rate law and explain
    2. Discuss the mechanisms of bimolecular surface reactions with a specific example.

Deduce the rate expression for each case.

  1. In the study of the kinetics of chlorination of phenol and mono substituted phenols by t-butyl hypochlorite in aqueous alkaline medium, the following data were obtained.

 

(i) At constant [substrate]0, and [OH–], the plots of log[t-BuOCl] vs time were linear. (ii) At constant [t-BuOCl]0 and [OH–], the rate increased with increase in [substrate] with first order dependences with all phenols.  The plots of kobs vs [phenol] were linear with zero intercepts on the ordinates.  (iii) The rate decreased with increase in [OH–] at fixed [t-BuOCl]0 and [phenol] for the chlorination of all phenols. The plots of kobs vs 1/[OH–] gave straight line passing through the origin (iv) Variation of ionic strength of the medium had negligible effect on the rates of chlorination.  (v) The decrease in the dielectric constant of the medium increased the rate.   Propose a suitable mechanism to account for the above data and explain.

 

 

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