When primary amines are treated with $HCl$,the product obtained is

The increasing basicity order of the following compounds is:
$(1)$ $CH_3CH_2NH_2$
$(2)$ $(CH_3CH_2)_2NH$
$(3)$ $(CH_3)_3N$
$(4)$ $PhNHCH_3$

$A$ compound $(x)$ with molar mass $108 \ g \ mol^{-1}$ undergoes acetylation to give a product with molar mass $192 \ g \ mol^{-1}$. The number of amino groups in the compound $(x)$ is . . . . . .

Which one of the following amides will not undergo the Hoffmann bromamide reaction?

Arrange the following in increasing order of their basic strength:
$(i)$ $C_2H_5NH_2, C_6H_5NH_2, NH_3, C_6H_5CH_2NH_2$ and $(C_2H_5)_2NH$
$(ii)$ $C_2H_5NH_2, (C_2H_5)_2NH, (C_2H_5)_3N, C_6H_5NH_2$
$(iii)$ $CH_3NH_2, (CH_3)_2NH, (CH_3)_3N, C_6H_5NH_2, C_6H_5CH_2NH_2$

How can aniline be purified?