Chem 113-final 2005

(B. Sc. Biochemistry) First Semester 2006 Subject: Chem 113 (Inorganic Chemistry)

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 full marks. Group (A) Long Questions (Any three)

(3× ×14 = 42)

Group (B) Short Questions: (Any six)

(6× ×7 = 42)

1. a)List the rules for the LCAOs .Show how the LCAO approximation gives rise to bonding and anti-bonding orbitals. Illustrate your answer by giving suitable example. b) Write down the biological importance of alkali metals. 2. a) What do you mean by crown ether and crypts? Explain giving suitable examples. b) Draw the structure of B12 unit found in solid structure of Boron .What is this shape called? 3. What are d- block elements? Discuss complex formation in case of 3dtrasition elements. 4. a) Explain the term lattice energy as applied to an ionic solid .Write down the Born lande equation and define the terms in it. b) Calculate the value of Madelung constant A-for MgO. Given r0 =2.10Ao , U0=-3940 KJmol-1 and E=4.8 X10-10 e.s.u. n=7 , N=6.02 X1023,

1. Explain with the help of energy level diagram the magnetic behavior of O2 , O2+ , O2 – , and also calculate the bond order of these molecules. 2. Write down short notes on: i) Interstitial alloy ii) substitutional alloy 3. Draw the structure of NaCl and TiO2 showing clearly the coordination number of cation and anion. 4. Discuss the oxidation state of elements of group IIIA with special reference to inert pair effect. 5. Why is [Ti( H2O)6]3+ ion violet in color? 6. Discuss the electronic configuration of 3d- series of elements. Why is the ionization energy for Copper and Chromium anomalously high? 7. Draw the geometric shape of SF6, BF4-, I3- and explain these structure using VSEPR theory. 8. What do you mean by Band theory?

Group (C) Very Short (Any eight)

(2× ×8 = 16)

1. Give two examples of two molecules having both and bond. 2. Compounds of alkali metals are colourless but Na2CrO4 and KMnO4 are coloured. Why? 3. Which one is more stable NaF or CsF? 4. Why oxygen is paramagnetic? 5. Why covalent compounds are insulator? 6. What do you mean by superconductivity? 7. Give examples of acid ligands. Why are they called so? 8. Transition metals are less electropositive than s- block elements. Why? 9. Why Cu+ is diamagnetic but Cu2+ is paramagnetic in nature? 10. What are Schotky defect? 11. What change will you observe in lattice energy when inter-ionic distance increases? 12. Hydrated AlCl3 is ionic in nature while anhydrous AlCl3 is covalent. Why?