Assertion (A) & Reason (B) MCQ

Question 11 Mark

Assertion (A): Aldehydes and ketones show condensation reactions.
Reason (R): The hydrogen atoms attached to $\alpha$-carbon of aldehydes and ketones are reactive.

Answer

(a) Both A and R are true and R is the correct explanation of A.
Explanation: The release of hydrogen from $\alpha$-carbon of aldehydes or ketones results in the formation of carbanion which is resonance stabilised. It is called enolate. Enolate ion can act as as a nucleophile and can attack the carbonyl group of the other molecule, i.e. giving condensation reactions.

View full question & answer→

Question 21 Mark

Assertion (A): Ammonolysis of alkyl halides is not a suitable method for the preparation of pure primary amines.
Reason (R): Ammonolysis of alkyl halides yields mainly secondary amines.

Answer

(c) Assertion (A) is true, but Reason (R) is false.
Explanation: The amine formed reacts further with more of alkyl halide to give 2º and 3º amines and finally quaternary salt

View full question & answer→

Question 31 Mark

Assertion (A): Cellulose can be easily converted into fibres.
Reason (R): Cotton contains about 90% cellulose.

Answer

(b) Both A and R are true but R is not the correct explanation of A.
Explanation: Cellulose is a linear condensation polymer of β-glucose. Because of linear structure, cellulose can be easily converted into fibres.

View full question & answer→

Question 41 Mark

Assertion $(A):$ Dehydration of glycerol with $\ce{KHSO_4}$ gives acrolein.
Reason $(R):$ Acrolein is an $\alpha , \beta-$unsaturated aldehyde.

Answer

Removal of two molecules of water gives a product which tautomerises to yield acrolein $-$an $\alpha, \beta-$unsaturated aldehyde.

View full question & answer→

Chemistry Assertion (A) & Reason (B) MCQ

Test yourself on this topic