Question

Statement-I : $\text{KMnO}_4 \xrightarrow{\Delta} \text{NH}_2$ followed by $\text{Br}_2/\text{KOH} \rightarrow \text{NH}_2$.
Statement-II : $\text{CH}_3\text{NH}_2 \xrightarrow{(i) \text{ Br}_2/\text{H}_2\text{O}, (ii) \text{ NaNO}_2/\text{HCl}, (iii) \text{ H}_3\text{PO}_2/\Delta} \text{CH}_3\text{Br}$.

• A. Statement-I and Statement-II both are correct
• B. Statement-I is incorrect Statement-II is correct
• C. Statement-I is correct Statement-II is incorrect
• D. Statement-I and Statement-II both incorrect

Hint:

Hofmann Bromamide Degradation ($\text{Br}_2/\text{KOH}$) converts primary amides to primary amines, losing one carbon atom. Diazotization of $1^\circ$ aliphatic amines leads to rapid decomposition, generally not yielding stable products.

Answer 1

The Correct Option is A

To determine the correctness of the statements provided, let's analyze each reaction separately.

Statement-I: 

The sequence of reactions is \(\text{KMnO}_4 \xrightarrow{\Delta} \text{NH}_2\) followed by \(\text{Br}_2/\text{KOH} \rightarrow \text{NH}_2\).

The first part of the reaction suggests heating with \(\text{KMnO}_4\). However, there seems to be a typographical error or inconsistency as \(\text{KMnO}_4\) doesn't directly lead to an \(\text{NH}_2\) group. The second part is related to the Hofmann bromamide reaction where an amide reacts with \(\text{Br}_2/\text{KOH}\) to form an amine with one less carbon atom. Assuming the initial compound that reacts with \(\text{Br}_2/\text{KOH}\) is already an amide, the reaction could indeed yield an \(\text{NH}_2\) group.

Thus, we can consider the statement constructively correct under these assumptions.

Statement-II:

The reaction \(\text{CH}_3\text{NH}_2 \xrightarrow{(i) \text{ Br}_2/\text{H}_2\text{O}, (ii) \text{ NaNO}_2/\text{HCl}, (iii) \text{ H}_3\text{PO}_2/\Delta} \text{CH}_3\text{Br}\) describes a multi-step transformation:

1. Step (i): Reaction with \(\text{Br}_2/\text{H}_2\text{O}\) forms a haloamine.
2. Step (ii): Treatment with \(\text{NaNO}_2/\text{HCl}\) forms a diazonium salt.
3. Step (iii): Reaction with \(\text{H}_3\text{PO}_2/\Delta\) involves reduction to replace the diazonium group with a bromine atom via Sandmeyer's reaction.

This sequence correctly converts \(\text{CH}_3\text{NH}_2\) to \(\text{CH}_3\text{Br}\) through formation and substitution of the diazonium group.

Thus, both statements are describing valid chemical transformations, making both statements correct. Therefore, the correct answer is:

Statement-I and Statement-II both are correct.