The carbylamine (isocyanide) test with $\mathrm{CHCl}{}_3$ and alcoholic KOH on warming is positive for

The carbylamine reaction needs a primary amino group $-\mathrm{NH}{}_2$, which gives a foul-smelling isocyanide $\mathrm{R}-\mathrm{NC}$. Secondary and tertiary amines do not. Only ethylamine is primary.