Question

Chloromethane on treatment with excess of ammonia yields mainly ______.

Options

• N, N-Dimethylmethanamine  

  \[\begin{array}{cc}
  \phantom{..............}\ce{CH3}\phantom{}\\
  \phantom{.........}/{}\phantom{}\\
  \phantom{}\ce{CH3 - N\phantom{..}\\
  \phantom{.........}\backslash{}\phantom{}\\
  \phantom{..............}\ce{CH3}\phantom{}\\
  \ce{}}
  \end{array}\]

• N–methylmethanamine (CH₃—NH—CH₃)

• Methenamine (CH₃NH₂)

• Mixture containing all these in equal proportion

Answer 1

Chloromethane on treatment with excess of ammonia yields mainly Methenamine (CH₃NH₂).

Explanation:

Chloromethane on treatment with excess of ammonia yields mainly methenamine.

\[\ce{CH3Cl + NH3 –> CH3NH2 + HCl}\]

Excess Methanamine

\[\ce{CH3Cl + \underset{Excess}{NH3} -> \underset{methenamine}{CH3NH2} + HCl}\]

However, if the two reactants are present in the same amount, a mixture of the primary, secondary and tertiary amine is obtained.

\[\ce{CH3Cl + NH3 -> \underset{(Primary amine)}{CH3NH2} + HCl}\]

\[\ce{CH3NH2 + CH3Cl -> \underset{(Secondary amine)}{(CH3)2NH}+ HCl}\]

\[\ce{(CH3)2NH + CH3Cl -> \underset{(Tertiary amine)}{(CH3)3N} + HCl}\]

\[\ce{(CH3)2NH + CH3Cl -> \underset{(Quarternary ammonium salt)}{(CH3)4 \overset{+}{N} \overset{-}{Cl}}}\]