In the chemical reaction, ${\text{CH}}_3{\text{CH}}_2{\text{NH}}_2+{\text{CHCl}}_3+3\text{KOH}\to A+B+3{\text{H}}_2\text{O}$, the compound $(A)$ and $(B)$ are respectively:

This is the Hofmann's Carbylamine reaction. Primary amines (aliphatic or aromatic) react with chloroform and ethanolic potassium hydroxide to form foul-smelling isocyanides (carbylamines).
$${\text{R-NH}}_2+{\text{CHCl}}_3+3\text{KOH}\to \text{R-NC}+3\text{KCl}+3{\text{H}}_2\text{O}$$
For ethylamine (${\text{C}}_2{\text{H}}_5{\text{NH}}_2$):
$${\text{C}}_2{\text{H}}_5{\text{NH}}_2+{\text{CHCl}}_3+3\text{KOH}\to {\text{C}}_2{\text{H}}_5\text{NC}+3\text{KCl}+3{\text{H}}_2\text{O}$$
$A={\text{C}}_2{\text{H}}_5\text{NC}$ (ethyl isocyanide) and $B=3\text{KCl}$.