Acetone and acetaldehyde are differentiated by

${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}\equiv \mathrm{N}+\left[\mathrm{H}\right]\stackrel{{\mathrm{SnCl}}_2/\mathrm{HCl}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{CHO}+{\mathrm{NH}}_3$

The above reaction is a:

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}\underset{\mathrm{Red} \mathrm{P}}{\overset{{\mathrm{Br}}_2}{\to }}\mathrm{X}\stackrel{{\mathrm{NH}}_3 \left(\mathrm{alcoholic}\right)}{⟶}\mathrm{Y}$

In the above reaction, $\mathrm{Y}$ is