Nalanda Open University 2009 B.Sc Chemistry Bachelor of Science, Final , Part-III, (Hons.) -VII - Question Paper

Bachelor of Science, Final Examination, 2009 Part-III, Chemistry (Hons.) Paper-VII

Nalanda Open University

Bachelor of Science, Final Examination, 2009 Part-Ill, Chemistry (Hons.)

Paper-VII

Time : 3.00 Hrs.    Full Marks : 15)

Answer any five questions.

1.    Explain the following Statement:

(i)    Cyclobutadiene is not aromatic compound

(ii)    Cyclopropenyl cation is aromatic but cyclopropenyl anion is not aromatic.

(iii)    Fulvene is an aromatic compound.

(iv)    Methyl group in toluene is an activator and ortho- and para-directors for further substitution in the ring.

(v)    Pyrrole is weakly acidic whereas pyridine is weakly basic

(vi)    Phenolphthalein is used as indicator in acid-base titrations.

(vii)    Ice has less density than water.

(viii)The    electrophillic substitution in naphthalene takes place at position-1

2.    On the basis of modern theory discuss the directive effect of -OH, -Cl, -N0₂ and -COOH groups during the electrophillic aromatic substitution.

3.    How has constitution of Uric acid been determined? And also give synthetic evidence in favour of the accepted structure of Uric acid.

4.    Give the synthesis and uses of any four of the following:

(i) Phenolphthalein (ii) Malachite green (iii) Congo red

(iv) Methyl Orange (v) Indigo

5.    How will you prepare anthracene by any two of the following:

(i) Howorth Synthesis    (ii) Friedel-Craft Reactions

(iii) Diels- Alder reaction.

6.    Describe the synthesis of Quinoline by: (i) Skraup Synthesis (ii) Friedlander Synthesis. How does Quinoline react with (a) Mixture of fuming HN0₃+H₂S0₄ (B) Sodamide (c) KOH.

Jj. Discuss the degradative and synthetic method for ascertaining the structure of isoflavones.

8.    (a) Explain the mechanism of unsymmetrical molecule over to unsymmetrical alkene.

(b) What is meant by anti-Markovnikov ie kharash peroxide effect.

or

Explain in terms of inductive effect on acidity order as given below:

ClCH₂COOH DHCOOH DCHsCOOH

9.    Discuss the Preparation and application of following reagent.

(i) Lithium aluminiumhydride    (ii) Hydrogen Peroxide

(iii) Peracetic acid.

10.(a)    Discuss briefly the method of isolation of ortho-para and meta-isomers from a mixture obtained by disubstitution of benzene.

(b) Write short notes on Triphenylmethane dyes.

Attachment: nalanda-open-university-2009-b-sc-chemistry-40543-1.tif

Earning:   Approval pending.