Question: 50: The product formed from the following reaction sequence is :
Answer: Option (2)
Explanation:
The given starting compound is benzaldehyde,
\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CHO}.
In the first step, benzaldehyde reacts with HCN to form a cyanohydrin.
\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CHO} + \mathrm{HCN} \rightarrow \mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CH(OH)CN}In the second step, acidic hydrolysis converts the nitrile group into a carboxylic acid,
forming mandelic acid.
\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CH(OH)CN} \xrightarrow{\mathrm{H}_{3}\mathrm{O}^{+}} \mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CH(OH)COOH}In the third step, heating with soda lime (\mathrm{NaOH} and \mathrm{CaO}) causes decarboxylation.
\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CH(OH)COOH} \xrightarrow{\mathrm{NaOH},\,\mathrm{CaO},\,\Delta} \mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CH}_{2}\mathrm{OH}Thus, the final product formed is benzyl alcohol.
Therefore, the correct option is (2).