Which of the following reagents converts phenyl methyl ketone into ethylbenzene?

The reaction $R-C(=O)-R + HCN \xrightarrow{\text{catalyst}} R-C(OH)(CN)-R$ is a nucleophilic addition reaction. Which of the following can be used as a catalyst in the above reaction?

The product $(C)$ of the reaction is:

Identify the correct option regarding the distinction between pairs of compounds.

$A$ well-known reagent which contains copper sulphate,sodium potassium tartrate,and sodium hydroxide is

One mole of an organic compound requires $0.5$ mole of oxygen to produce an acid. The compound may be