In a set of reactions, propionic acid yielded a compound (D). The structure of ‘D’ would be

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}\stackrel{\mathrm{SOC}{l}_2}{\to }\left(\mathrm{B}\right)\stackrel{{\mathrm{NH}}_3}{\to }\left(\mathrm{C}\right)\underset{{\mathrm{Br}}_2}{\overset{\mathrm{KOH}}{\to }}\left(\mathrm{D}\right)$

 

Step1: Formation of acid chloride

Step 3:- Hofmann’s bromide reaction

By this method, the acid amide $\left({\text{-CONH}}_{\text{2}}\right)$ group is converted into primary amine   $\left({\text{-NH}}_2\right)$ group