B. Sc. (VI Semester) Examination
CHEMISTRY
Paper: CHEM-362
(Inorganic Chemistry)
Full Marks : 80
Pass Marks : 35%
Time : Three Hours
Note: (i) Answer all the questions.
(ii) The figures in the margin indicate full marks for the questions.
1. Answer the following questions: 2x5= 10
(a) Explain why [ScF6]3- is colourless while [TiF6]3- is coloured.
(b) Explain why boron nitrides are insulators while graphite is conductor through both have hexagonal layered structure.
(c) What is EAN rule? Explain.
(d) What is Zaise’s salt? How it is prepared?
(e) Give two examples of use of chelating ligands in the treatment of metal toxicity.
2. Answer any four questions: 4x5 = 20
(a) Calculate in units of Δo, the CFSE of CO2+ and Mn2+ ions in their high-spin and low-spin slates.
(b) Give one method each for preparation of borazine and silicone.
(c) Discuss bonding in Ni(CO)4 using valence Bond Theory and predict its structure.
(d) What is Ziegler-Natta Catalyst? Explain its role in polymerization of ethane.
(e) Discuss the toxic effects of pb, cd and Hg.
3. Answer any five questions: 5x10 = 50
(a) (i) [NiBr4]2- and Ni (CO)4 are both tetrahedral in shape. While [NiBr4]2- is paramagnetic, Ni (CO)4 is diamagnetic. Explain.
(ii) State and explain Jahn-Teller effect in Octahedral complexes.
(b) (i) Discuss structural aspects of different types of silicates. What is silicon grease and silicon rubber.
(ii) What is polymetaphosphate? How are polymetaphosphoric acid obtained.
(c) (i) How Fe (CO)5, CO2(CO)8 and Fe2(CO)9 are prepared by direct synthesis, reductive carbonylation and by thermolysis respectively.
(ii) Show that each Mn atom in Mu2 (CO)10 follows 18-electron rule.
(d) (i) Discuss the mechanism of hydrogenation of ethane using Wilkinson’s catalyst.
(ii) What are metallocenes? Give one example of preparation of ferrocene in commercial scale.
(e) Discuss the structure of chlorophyll and explain its importance in photosynthesis.
(f) (i) What are stepwise and overall formation constant? What is the relation between them?
(ii) What is Irving William series? What is its use?
(iii)Why tetrahedral complexes are mostly high spin?
