Question 1

Which of the following compounds will undergo aldol condensation?

Accepted Answer

Acetaldehyde (CH3CHO) contains alpha-hydrogen atoms, which are acidic in nature due to the electron-withdrawing effect of the carbonyl group. Compounds containing alpha-hydrogen atoms undergo aldol condensation in the presence of a dilute base. Formaldehyde, benzaldehyde, and 2,2-dimethylpropanal do

Question 2

Rosenmund reduction is used for the preparation of:

Accepted Answer

Rosenmund reduction involves the catalytic hydrogenation of acyl chlorides (acid chlorides) over palladium poisoned with barium sulfate (BaSO4). This reaction selectively stops at the aldehyde stage and prevents further reduction to alcohols.

Question 3

Which reagent is used in Clemmensen reduction?

Accepted Answer

Clemmensen reduction involves the reduction of carbonyl compounds (aldehydes and ketones) to hydrocarbons using zinc amalgam (Zn-Hg) and concentrated hydrochloric acid (HCl).

Question 4

Tollens' reagent is:

Accepted Answer

Tollens' reagent is ammoniacal silver nitrate solution Ag(NH3)2+ OH-. It is used to distinguish between aldehydes and ketones. Aldehydes reduce Tollens' reagent to form a bright silver mirror on the inner walls of the test tube.

Question 5

Cannizzaro reaction is not given by:

Accepted Answer

Cannizzaro reaction is given by aldehydes that do not possess alpha-hydrogen atoms. Acetaldehyde (CH3CHO) contains three alpha-hydrogen atoms and therefore undergoes aldol condensation, not Cannizzaro reaction.

Aldehydes, Ketones and Carboxylic Acids — CBSE Class 12 Chemistry Important Questions & Revision Notes