Chem 113-internal 2004

Universal Science College Internal Examination Subject: Chem 113 (Inorganic Chemistry) Date: Feb. 13 , 2005

(B. Sc. Biochemistry) First Semester 2005

Full Marks: 100 Pass Marks: 45 Time: 3 hours

Candidates are required to give their answers in their own words as far as practicable. The figure in the margin indicates the full marks. Group A (3× ×14 = 42)

Long Questions (Any three ) 1.

What is LCAO approximation? Discuss any two possible combination of orbitals.

2.

Write down the theories of bonding in metals. Explain band theory of metals and also explain conductors, insulators and semiconductors on the basis of band theory.

3.

(a) What do you mean by alkalimetals? Write down its general properties. (b) Why Li shows similar properties of Mg? Write down the reason for Li having greater tendency to form covalent compounds. Li R is important write its great importance with reactions.

4.

What are transition elements? Explain the colour of transition metal complexes on the basis of crystal field theory. Group - B

Short Questions: (Any six) (6× ×7 = 42) 1. Write notes on: (i) π bond σ bond (ii) Structure of BF4 BF4- ion. Using VSEPR theory. 2. What do you mean by crown and cryptate? Explain with examples. 3. (a) What are the factors on which lattice energy depends? (b) Use Born lande equation to calculate the lattice energy of K Br for which A = 1.748, r = 3.28 A0, n = 9.5, e = 4.8 x 10-10 esu [10 ergs = 1J] 4. Explain M.O.T. in hetero nuclear molecule with example of CO and NO . Draw energy level diagram and B.O 5. What do you mean by alloy? Explain and write down the types of alloys. 6. Explain O.S. in III A group in P.T. and types of bond found by different elements in this group. 7. What is Ziggler's Natta catalyst? Write down its mechanism. 8. Write down the reasons for formation of complexes by transition elements. Group – C Write short notes on: (Any eight) (2× ×8 = 16) 1. Why covalent compounds are insulator? 2. How metals have characteristics metallic luster? 3. What do you mean by non bonding combinations of orbital? 4. Conductivity of metals decreases with temperature, but opposite occurs with semiconductors why? 5. Why ionic compounds are soluble in polar solvent? 6. Alkali metals having body centred cubic structure why? 7. What is redius ratio? 8. What are nonstoichiometric defects? 9. What is the cause of inert pair effect in group III A? 10. What is a cluster compound? 11. Why Ti 4+ is colorless and Ti3+ is purple? 12. Give two examples of the transition metal compounds in which M – M bond is present. ***