The $Wolff-Kishner$ reduction is used for which of the following?

Assertion : Benzaldehyde is more reactive than ethanol towards nucleophilic attack.
Reason : The overall effect of $-I$ and $+R$ effect of phenyl group decreases the electron density on the carbon atom of $>C=O$ group in benzaldehyde.

Identify an aldehyde used in margarine and in food for its buttery odour.

The reaction shown below proceeds via which mechanism?

The reaction of $50\%$ aq $KOH$ on an equimolar mixture of $4-$methylbenzaldehyde and formaldehyde followed by acidification gives

Formaldehyde can be distinguished from acetaldehyde by the use of