Aldehydes | MCQs

Explanation

Aldol condensation requires at least one α-hydrogen (hydrogen on the carbon next to the carbonyl group).

Benzaldehyde and formaldehyde lack α-hydrogens, so they cannot undergo Aldol condensation.

Explanation

Aldehydes and ketones contain a polar carbonyl group (C=O) which is susceptible to nucleophilic attack.

They commonly undergo nucleophilic addition reactions, a key feature of their reactivity.

Explanation

Fehling's test is used to identify aldehydes by producing a red precipitate.

Aldehydes reduce Fehling’s solution, unlike ketones.

Explanation

The reactivity of aldehydes towards nucleophilic addition depends on the size of the alkyl group attached to the carbonyl carbon.

Formaldehyde (HCHO) has no alkyl groups attached to the carbonyl carbon, making it the most reactive

Because there is no steric hindrance, and the electron-donating effect is minimal.

Explanation

When an aldehyde is oxidized, it typically converts to a carboxylic acid.

This reaction involves the addition of an oxygen atom to the aldehyde, changing the carbonyl group (C=O) at the end of the carbon chain into a carboxyl group (–COOH).