Question

From the above reactions, the number of reaction(s) that produce(s) benzaldehyde is

Answer 1

All four reactions produce benzaldehyde.

(I) This is Gatterman-Koch formylation. Benzene is treated under high pressure with CO and HCl in the presence of $anhyd.AlC{l}_3/CuCl$ catalyst to form benzaldehyde.

(II) Hydrolysis of benzyl chloride by heating with water will give benzaldehyde.

(III) This is a Rosenmund reduction. Benzoyl chloride is hydrogenated over

$Pd-BaS{O}_4$ catalyst to give benzaldehyde.

(IV) Partial reduction of methyl benzoate with DIBALH in the presence of toluene as a solvent at $-{78}^{0}C$ gives benzaldehyde.

Ans-$4$