LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

   B.Sc. DEGREE EXAMINATION – CHEMISTRY

FIRST SEMESTER – NOVEMBER 2010

CH 1503 – CONCEPTS IN INORGANIC CHEMISTRY

 

 

 

Date : 12-11-10                     Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

PART – A

 

Answer ALL the questions:                                                                          (10 × 2 = 20 marks)

 

1. Size of Cl^– ion is greater than that of Chlorine atom – Explain.
2. Define Ionisation energy.
3. What is Aufbau principle?
4. What is inert pair effect?
5. Define bond order.
6. What is Lewis concept of acids and bases?
7. What are interstitial compounds?
8. Explain why O₂ is paramagnetic whereas O₂^2– is diamagnetic.
9. Which is more soluble in water MgSO₄ or BaSO₄? Why?
10. Find the oxidation number of

• Mn in KMnO₄ 2) S in  H₂S₂O₈.

PART – B

 

Answer any EIGHT questions:                                                                    (8 × 5 = 40 marks)

 

11. Explain the following processes
12. Smelting  b) Froth floatation.                                                                                              (2+3)
13. Define Electron affinity. Explain its trend across the period and down the group of periodic table.
14. Describe the factors favouring the formation of covalent bond in reference to Fajan’s rule.
15. Explain ‘Ellingham diagrams’.
16. Lithium shows greater resemblance with magnesium than with other alkali metals.
17. What are the postulates and limitations of Valence bond theory?
18. Draw the M.O diagram for NO molecule and explain its magnetic behavior.
19. What do you mean by inter and intra molecular hydrogen bonding?Discuss the effect of H-bonding on melting point and boiling point of substances.
20. What are bonding and antibonding molecular orbitals?

 

20. Write a note on clathrates.
21. Explain Pearsons’s concept of hard and soft acids. Give examples.
22. Balance the following chemical reaction by ion- electron method

MnO₄^– + C₂O₄^2– à Mn²⁺ + CO₂   (in acidic medium).

 

PART – C

 

Answer any FOUR questions:                                                                                (4 × 10 = 40  marks)

 

23. What is electronegativity? How do you calculate electronegativity on the basis of
24. Pauling’s approach        b) Mulliken’s approach                                                        (2+4+4)

 

24. Define lattice energy and solvation energy. Describe how lattice energy of ionic solids is evaluated by Born-Haber cycle.

 

25. Define Hybridisation. On the basis of hybridization discuss the geometry of the following molecules.

• SF₆        2) PCl₅            3) NH₃            4) XeF₄                                                                   (2+8)

 

26. a) Explain the postulates of VSEPR theory.                                                                                  (6)

 

1. b) Differentiate between a σ bond and a π bond. With an example.             (4)

 

27. a) Distinguish between cubic close packing and hexagonal close packing of spheres. (6)

 

1. b) Give reasons for the following:

1) H₂S is a gas H₂O is a liquid

 

2) Diamond is a hard substance while graphite is soft.                                                       (4)

 

27. Describe the following reactions in liquid ammonia giving suitable examples.

 

1. a) Acid-base reactions
2.    b) Precipitation reactions
3.    c) Complex formation reactions
4. d) Ammonolysis