b
\(\mathrm{CH}_3\left(\mathrm{CH}_2\right)_5 \mathrm{COOC}_2 \mathrm{H}_5 \xrightarrow{\text { DB. } 4 \text { L-H. } \mathrm{H}_2 \mathrm{O}} \mathrm{CH}_3\left(\mathrm{CH}_2\right)_5 \mathrm{CHO}\)

\(\mathrm{C}_6 \mathrm{H}_5 \mathrm{COC}_6 \mathrm{H}_5 \xrightarrow{\mathrm{Zn}(\mathrm{Hg}) \& \text { conc. } \mathrm{HCl}} \mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{C}_6 \mathrm{H}_5\)

\(\mathrm{C}_0 \mathrm{H}_5 \mathrm{CHO} \xrightarrow[\mathrm{H}, \mathrm{O}]{\mathrm{CH}_3, \mathrm{Mgr}} \mathrm{C}_0 \mathrm{H}_5 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_5\)

\(\mathrm{CH}_3 \mathrm{COCH}_2 \mathrm{COOC}_2 \mathrm{H}_5 \xrightarrow{\text { Nath }, \mathrm{H}^{+}} \mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_2 \mathrm{COOC}_2 \mathrm{H}_5\)