Dibrugarh University Question Paper - Chemistry – Science - (May'2019)

 

2019

(May)

CHEMISTRY

(General)

Course: 601

(Organic Chemistry)

The figures in the margin indicate full marks for the questions

(New Course)

Full Marks: 32

Pass Marks: 10

Time: 2 hours

UNIT - I

1. (a) How will you prepare ethyl acetoacetate from ethyl acetate?                          1

(b) How will you prepare the following (any two):                        1½x2=3

1)         Succinic acid from ethyl acetoacetate.

2)         Cyclobutane carboxylic acid from diethyl malonate.

3)         Crotonic acid from ethyl acetoacetate.

UNIT – II

2. (a) How will you prepare tartaric acid from acetylene? What happens when potassium sodium tartrate reacts with copper sulphate and sodium hydroxide?                                              1+1=2

(b) What happens, when (any one) –

1)         Citric acid is reduced with hydrogen iodide;

2)         Phthalic acid is reduced with sodium amalgam and sodium carbonate solution?

(c) Write the product of the following reactions (any two):                     1x2=2

    

UNIT – III

3. Answer the following:                               1½x2=3

a)         How will you prepare?

1)         Anthracene by Diels-Alder reaction.

2)         Naphthalene by Fitting synthesis.

b)         Complete the following reactions (any two):                                             1x2=2


c)          Explain why (any one):                                        2

1)         Furan undergoes electrophilic substitution reaction at C-2.

2)         Pyrrole is weaker base than pyridines.

Or

4. (a) How will you obtain the following:                                1½x2=3

1)         Pyridine from Pyrrole.

2)         Furan by Paal-Knorr synthesis.

3)         M-nitrotoluene from p-nitrotoluene.

(b) What happens when –                                       1+1=2

1)         Naphthalene is oxidized with at 733 K – 753 K;

2)         Pyridine is reduced with Ni catalyst?

(c) Explain why (any one):                                        2

1)         Pyrrole is more reactive than furan in electrophilic substitution reaction.

2)         Pyrrole shows aromatic character.

UNIT – IV

5. (a) How will you obtain the following (any two)?                          1x2=2

1)         Cinnamic acid from benzaldehyde.

2)         Benzophenone from benzene.

3)         Benzaldehyde from benzene.

(b) Complete the following reactions (any three):                        1x3=3



(c) Answer any one of the following:                                  2

1)         Explain why chloroacetic acid is stronger acid than bromoacetic acid.

2)         Why formaldehyde does not undergo Aldol condensation reaction?

(d) What happens, when (any one) -                                  1

1)         Benzoic acid is reduced with lithium aluminium hydride;

2)         Acetic acid reacts with chlorine in presence of red phosphorus?

UNIT – V

6. (a) Answer any two of the following:                                                 2x2=4

1)         What are the essential amino acids? Explain with examples.

2)         Distinguish between RNA and DNA.

3)         Write a short note on mutarotation.

(b) Answer any one of the following:                                  1

1)         Give an example of fibrous protein.

2)         Draw the open chain structure of D-glucose in Fischer projection.

UNIT – VI

7. (a) Answer any one of the following:                                                 2

1)         Write a short note on condensation polymerization.

2)         What is buna-S-rubber? How is it prepared?

(b) Write the monomer necessary for the preparation of Nylon-6.                     1

(Old Course)

Full Marks: 32

Pass Marks: 13

Time: 2 hours

UNIT – I

1. (a) What do you mean by keto-enol tautomerism? Explain with example.                        2

(b) How will you obtain the following (any two)?                                           1½x2=3

1)         Butanoic acid from ethyl acetoacetate.

2)         Adipic acid from diethyl malonate.

3)         Propanone from ethyl acetoacetate.

UNIT – II

2. (a) Write the synthesis of the following (any one):                      1

1)         Lactic acid from propanoic acid.

2)         Crotonic acid from crotonaldehyde.

(b) What happens, when (any one) –                                                 1

1)         Phthalic acid is heated at its melting point;

2)         Citric acid is heated with HI?

(c) Complete the following reactions (any two):                                                            1x2=2



UNIT – III

3. Answer either (a), (b) and (c) or (d), (e) and (f)

a)         How will you obtain the following (any two)?                                            1½x2=3

1)         Furan by Paal-Knorr synthesis.

2)         Saccharin from Anthranilic acid.

3)         Anthracene by Haworth’s synthesis.

b)         Complete the following reactions (any two):                                             1x2=2



c)          Explain any one of the following:                                                    2

1)         Furan undergoes electrophilic substitution reaction at C-2.

2)         Pyrrole is weaker base than pyridines.

d)         How will you obtain the following:                                                                 1½x2=3

1)         Thiophene from n-butane.

2)         Naphthalene from Haworth’s synthesis.

e)         Explain any one of the following:                                                    2

1)         Pyrrole shows aromatic behaviour.

2)         Pyrrole is more reactive than furan in electrophilic substitution reaction.

f)          What happens, when (any two) –                                                  1x2=2

1)         Nitrobenzene is treated with conc. and conc. .

2)         Nitrobenzene is reduced with Zn dust and aq. .

3)         Furan is reduced with raney nickel?

UNIT – IV

4. (a) Answer any two of the following:                                                                                 2x2=4

1)         How will you synthesize alanine by Strecker synthesis?

2)         Distinguish between RNA and DNA.

3)         What do you mean by essential and nonessential amino acids? Give two examples and draw their structure.

(b) Answer any one of the following:

1)         What is peptide bond?

2)         What is zwitterion in amino acid?

UNIT – V

5. (a) Write short note on any one of the following:                                         2

1)         Epimerization.

2)         Mutarotation.

(b) Answer any one of the following:

1)         How will you convert D-glucose to D-arabinose?

2)         What happens when glucose is treated with conc. HI in presence of red phosphorous? What information regarding the structure of glucose is obtained from this reaction?

(c) Draw the cyclic structure of D-glucose and D-fructose.

UNIT – VI

6. (a) Answer any two of the following:                                                                                 2x2=4

1)         Write a short note on addition polymerization.

2)         What is Bakelite? How is it prepared?

3)         What is urea-formaldehyde resin? How is it prepared?

(b) Name the monomers necessary for the preparation of the following (any one):                     1

1)         Terylene or Dacron.

2)         Buna-S-rubber.

 

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