Download OU B.Sc 2019 June-July 4th Semester 3115 Chemistry Question Paper

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B.Sc. IV-Semester (CBCS)

Subject

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Paper

PART - A

(Short)

Note : Answer any FIVE of the following questions.

1. Explain linkage, coordination and isomerism using suitable examples.

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2. Give the classification of organometallic compounds.
3. Arrange acetic acid, trimethyl acetic acid in the order of their acidity. Explain.
4. Write the mechanism for Claisen ester condensation.
5. What is cell constant? What are its units? Calculate the specific conductance if the electrodes are 2.2 cm apart.
6. Explain the terms Electrophoretic effect and relaxation effect.

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7. Explain thermal and photochemical pericyclic reactions.
8. Give the retrosynthetic analysis of phenyl ethyl bromide.

PART — B (4 x 15 = 60 Marks)

(Essay Answer Type)

Note: Answer ALL from the questions.

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1. (a) What is EAN rule? Calculate the EAN of the central atom in (i) K₃[Fe(CN)₆] (ii) [CoF₆]^3- (iii) [Cu(NH₃)₄]SO₄
   (b) How do you explain the formation of Ni(CO)₄, Fe(CO)₅ and Fe₂(CO)₉ on the basis of 18-electron rule?
2. (a) Discuss the special methods of preparation of aromatic acids.
   (b) Propose mechanism for acid catalysed ester hydrolysis.
3. (a) Propose mechanism for reduction reactions of nitrobenzene in different media.
   

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   (b) Write a note on conductometric titrations.
4. (a) What is Ostwald's dilution law? What are its uses and limitations?
   (b) Write a note on (i) glass electrode (ii) quinhydrone electrode
5. (a) (i) Define and explain enantiomeric excess and diastereomeric excess.
   (ii) Write a note on Target molecule, Synthon, synthetic equivalent, functional group interconversion.

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