Important Questions Class 12 Chemistry Chapter 12 – Aldehydes Ketones and Carboxylic Acids 1 Mark Questions

1. Give one use of Formalin.

Ans. Formalin is used as a disinfectant, preservative for biological specimens and in leather industry.

2. What is the chemical name of Tollen’s reagent and Fehling’s solution.

Ans. Tollen’s reagent  = Ammoniacal Silver Nitrate

Fehlings solution =  Sodium Potassium Tartarate.

3. Write the structure of alkenes that on ozonolysis will give ketone only.


4.  What is the function of in rosenmund reaction?

Ans. acts as a catalytic poison which prevents further reduction of aldehyde to alcohol.

5.  Name the isomers with molecular formula. Which one will have high boiling point?

Ans. The two isomers are and. Acetone boils at higher temperature due to presence of two electron donating alkyl groups.

6. Write a chemical test to distinguish between aldehyde and ketone.

Ans. Aldehydes and ketones can be distinguished by Tollen’s test. Aldehydes give a silver mirror on reacting with Tollen’s reagent whereas ketones will not react.

7. What happens when acetaldehyde is kept with a trace of sulphuric acid? Write the structure of product.

Ans. A trimer of acetaldehyde, called paraldchyde is formed.

8.  What is the Hofmann bromamide reaction? Illustrate with one example.

Ans. Hoffman bromamide reaction is a reaction in which amides are converted to amines of one carbon less than the starting amide. It is a very important step – down reaction.

9. Give IUPAC names of following









(ix) HOOC – CH = CH – COOH


Ans. (i).  5-Chloro -3- ethylpentan -2-one.

(ii). 2 –(2-bromophenyl) ethanal

(iii). 2- Phenylpropanal

(iv). 5- Chloro -3- methyl pentan -2-one

(v). 4- Hydroxypentan -2- one

(vi).  3- Methylbutan -2-one

(vii).  2- Ethyl -2- methylbutanoic acid

(viii).  2- (3- Bromophenyl) ethanal

(ix).  But-2- en -1,4 –dioic acid

(x).  4- Methoxybenzaldehyde

10. Draw the structure of the following –

(i) 4- Methoxybenzaldehyde

(ii) 5- Bromo -3- Chloro -2- iodobenzoic acid

(iii) 3,3 – Dimethyl -1- Chlorobutane

(iv) 2,3- Dihydroxy -4-methylpentanal

(v) 3- Hydroxy-2-methyl -propanal

(vi) 2,4 –Dimethyl -3- pentanone

(vii) 1,2 –Ethaneodioc acid

(viii) 3- Pentene -2-one

(ix) 1,3 – Propane –dioic acid

Ans. (i).









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