Class XII (Chemistry)

Holidays Homework Class XII Chemistry

Investigatory projects can make the study of chemistry exciting, enjoyable and educational. Project work develops scientific and cooperative attitude and self confidence. Keeping these objectives in view investigations work is included in holiday homework of Chemistry. A list of projects is given to students and may take up or select any one project for investigation.

1. To study of the conversion of waste cellulosic/starchy material into glucose.

2. You are living in a grouping Housing society of 150 families. Lay out a plan to recycle the waste water.

3. To prepare vegetable dyes.

4. To prepare a sample of Bakelite plastic.

5. A comparison of sugar contents of (a) various stages during ripening.

6. To prepare poster - colours

Very short answer type questions

1. In each of the following pairs of organic compound identify the compound which will undergo SN1 reaction faster.

2. Predict the order of reactivity of the following compounds in SN1 reaction,

3. Explain why thionyl chloride method is preferred for preparing alkyl chlorides from alcohols.

4. a) Arrange the following halides in order of increasing SN2 reactivity.

CH3Cl, CH3Br, CH3CH2Cl, (CH3)2 CHCl.

b) Arrange the following in order of increasing ease towards nucleophilic substitution. 4-nitrochlorobenzene, chlorobenzene, 2,4,6-tri-nitrochlorobenzene, 2, 4- dinitro chlorobenzene.

5. Give one chemical test to distinguish between C2H5Br and C6H5Br.

6. An optically active compound having molecular formula C7H15Br reacts with aqueous KOH to give a racemic mixture of products. Write the mechanism involved in the reaction.

7. Unlike phenols, alcohols are easily protonated?

8. How is that alcohol and water miscible in all proportions?

9. Mention two important uses of methanol.

10. O-nitrophenol has lower b.pt them p-nitrophenol.

11. What is wood alcohol?

12. What product is obtained when ethyl benzene is oxidized with alkaline KMn O4?

13. Mention one important use of methansic acid.

14. Mention one Industrial product manufactured from methanal.

15. What for are quaternary ammonium salts widely used?

16. Explain why AgCl is soluble in aqueous solution of methylamine.

17. For an amine RHN2, write the expression for Kb to indicate base strength.

18. Mention one commercial use of N, N-dimenthylaniline.

19. Why do amines act as nucleophiles?

20. Give one example of ambident nucleophiles.

SHORT ANSWER QUESTIONS

1. How are the following conversions can be carried out.
a) Aniline to Chlorobenzene
b) Aniline to Benzoic acid
c) Nitrobenzene to phenol.

2. Account for the fact that it is difficult to prepare pure amines by ammonolysis of alkyl halides.

3. Why amiline is a weaker base than Cyclohexylamine?

4. Describe chemical tests to distinguish between secondary amine and tertiary amine.

5. Illustrate the following with suitable examples
1) Hoffman’s bromamide reaction
2) Coupling reaction
3) Acylation reaction

6. a) Aqueous solution of methylamine reacts with iron (III) chloride to precipitate iron (III) hydroxides. b) Aniline reacts with bromine to give 2, 4, 6 tribromoaniline. +

7. Amines are more basic than alcohols. (Hint: RNH3 is more stable than + R-OH2)

8. CH3CONH2 is a weaker base than CH3CH2NH2

9. Do the following conversions
a) 4-Nitroaniline into 1,2,3-tribromo benzene
b) Aniline into 3,4,5- triiodonitrobenzene.

10. Why diazotisation of aniline takes place in ice cold conditions. (Hint: At higher temp. aniline changes to phenol)

11. Why primary aromatic amines cant be prepared by Gabriel phthalimide synthesis?

12. What organic compounds are used in artificial flavouring and perfuming?

13. Carboxylic acids do not give characteristic reactions of carbonyl group. Why?

14. How will you differentiate between a) Phenol & benzoic acid b) Propanone and ethanol c) Acetaldehyde and acetone.

15. Explain the following reactions
a) Rosenmund reduction
b) Cannizaro’s reactions
c) wolf-kishner reduction
d) stephan’s reduction
e) Etard reaction

16. How will you convert
a) Benzaldehyde into acetophenone
b) Acetaldehyde into but - 2-enal
c) Malonic acid into acetic acid

d) Benzamide to toluene
e) Benzye chloride to 2-phenylethanamine

17. Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Why?

LONG ANSWER TYPE QUESTIONS

1. Di-tert butyl ketone does not give a precipterte with NaHSO3 whereas acetone does. Why?

2. Dialkyl cadmium is considered superior to Grignard’s reagent for the preparation of a ketone from an acid chloride.

3. A compound X (C2H4O) on oxidation gives Y (C2H4O2). X undergoes haloform reaction. On treatment with HCN X forms product Z. While on hydrolysis gives 2-hydroxy – propanoic acid. a) Write down the structures of X & Y.
b) Name two products when X reacts with dil. NaOH (Write down reactions involved)

4. Write structural formulae and names of the four possible aldol condensation products from propanal and butanal. In each case indicate which aldeyhyde served as electrophile and which as nucleophile.

5. Write the structures of the major products expected from the following reactions.
a) Mononitration of 3-methylphenol
b) Dinitration of 3-nmethylphenol
c) Mononitration of phenylmethanoate.

6. a) Explain the observed Kb order

b) Mention a chemical property in which methoanoic acid differs form acetic acid.
c) Highly branched carboxylic acids are less acidic then unbranched acids.
d) How does a carbonyl group differ from an ethylenic bond?
e) How is CO converted into methanol?

7. Do the following conversions
a) Ehtanal to amino ethane (Hint (1) NH3 (2) Reduction
b) Cyclohexanol to cyclohexylamine (Hint (1) OXn (2) NH3/H2-Ni
c) Aniline to N-phenylethanamide
d) Ethanamide to Methylamine
e) Aniline to Benzyl alcohol
f) Nitrobenzene to Benzoic acid
g) Nitromethane to Ethanoic acid
h) Acetic acid to Acetaldyhyde
i) Acetic acid to Acetone
j) Phenol to Salicylaldehyde
h) Toluene to Benzaldehyde (Hing : Etard reaction)
i) Acetic acid to Methylamine
j) Benzonitrile to Acetophenone
Hint: 1) Hydrolysis
2) PCl3
3) (CH3)2 Cd/ dry ether.

k) Cumene to phenol
l) Ehtanol from But-2-ene

8. Write IUPAC names of the following