LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

GH 29

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FIRST SEMESTER – APRIL 2008

    CH 1809 – ANALYTICAL CHEMISTRY

 

 

 

Date : 05/05/2008            Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

PART A

Answer ALL questions                                                                  (10 ´ 2 = 20 Marks)

 

1. A method of analysis yields weights for gold that are low by 0.4 mg.

Calculate the percent relative error caused by this uncertainty if the weight

of gold in the sample is 0.4 g.

2. What is meant by retention time?
3. Mention one advantage and one disadvantage of flame ionization detector

in gas chromatographic separation.

4       .Illustrate displacement titration with an example.

5       In what respect Fajans method superior to the Volhard method for the

titration of chloride ion?

6. Explain any two factors that affect the thermogram.
7. Calculate the equivalent point potential in the titration of Fe²⁺ vs Ce^+4.

( SRP    Fe³⁺ /Fe⁺² = 0.68 V ;  Ce⁺⁴ / Ce⁺³ = 1.44 V)

8       .Illustrate metallochrome indicator with an example.

9. What are the limitations of Beer – Lambert’s law?
10. Write the Ilkovic equation and explain the terms.

 

PART B

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

 

11. A 7.27 x 10^-5 M solution of KMnO₄  has a transmittance of  44.1% when

measured in a 2.1 cm cell at a wave length of 525 nm. Calculate the

molar absorptivity of KMnO₄ .

12. Distinguish clearly between precision and accuracy.
13. Explain the various factors which affect the equivalence point in

complexometric titrations.

14. Draw the TG thermogram of calcium oxalate monohydrate obtained

when it is heated to 700^o C and explain.

15. Describe the flame ionization detector used in GC.
16. Explain the principle and application of capillary electrophoresis.
17. How is Cu²⁺ estimated by electrogravimetric method?
18. What are determinate and indeterminate errors and suggest the

methods for minimization of these errors.

19. Explain the components of a spectrofluorometer with a neat diagram.
20. What are the advantages of DME?
21. Explain the function of adsorption indicators in precipitation titrations.
22. What is meant by half-wave potential?What is its significance?

 

 

 

PART C

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

 

23. Describe with a block diagram the various parts of the instrument used in

AAS and explain the their functions.

24. a)Write briefly on masking and demasking agents.

b)Describe Fajans method for the estimation of chloride.

25. a)Explain the various factors which affect fluorescence emission .

b)Show that the equivalent point potential in the titration of ferrous ion

against permanganate is pH dependent.

26. Discuss the principle of Cyclic voltammetry and its use in the determination

of electrochemical reversibility and stability of a redox system.

27. Describe the HPLC instrument with a neat diagram and the different

types of columns employed.

28. Carry out a least -squares analysis of the experimental data obtained in

the chromatographic determination of iso-octane in a hydrocarbon mixture

and derive the equation for the best line through these ponts:

 

Mole pecent isooctane (x_i )                                         Peak area (y_i )

0.352                                                               1.09

0.803                                                               1.78

1.08                                                                 2.60

1.38                                                                 3.03

1.75                                                                 4.01

 

 

 

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