Question

Which amine yields N-nitroso amine after treatment with nitrous acid ($NaN{{O}_{2}}+HCl$)?

Answer 1

Hint: N-nitroso amine is a compound in which the nitrogen is attached to two alkyl or aryl groups with a single bond and the nitrous group is attached to that nitrogen atom through a single bond. So, the only secondary amine can only give N-nitrous amine when treated with nitrous acid.

Complete step by step answer:
N-nitroso amine is a compound in which the nitrogen is attached to two alkyl or aryl groups with a single bond and the nitrous group is attached to that nitrogen atom through a single bond. It is represented as:

So, the only secondary amine can only give N-nitrous amine when treated with nitrous acid. The secondary amines are those in which the nitrogen has only one hydrogen atom. Primary amines are those in which the nitrogen has two hydrogen atoms and tertiary amines are those in which the nitrogen doesn't have a hydrogen atom. So we have to check the compound in which secondary amine is present.

In this molecule, primary amine is present because the nitrogen has two hydrogen atoms, due to which it will not form N-nitroso amine.

In this molecule also primary amine is present because the nitrogen has two hydrogen atoms, due to which it will not form N-nitroso amine.

In this molecule tertiary amine is present because the nitrogen atom doesn’t have a hydrogen atom. So, it will not form N-nitroso amine.

In this molecule, the secondary amine is present because the nitrogen atom has one hydrogen atom and it will give N-nitroso amine. The reaction is given below:

Therefore, the correct answer is an option (d).

Note: When primary aryl amine reacts with nitrous acid then they form diazonium salts and when primary alkyl amine reacts with nitrous acid then they form alcohol. When tertiary alkyl amines react with nitrous acid they form soluble nitrite salts and when tertiary aryl amines react with nitrous acid they form p-nitroso amine.