Question

Assertion (A): Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
Reason (R): Diazonium salts of aromatic amines undergo resonance.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Hint:

Aromatic diazonium ions are stable enough to be used in Sandmeyer reactions because the benzene ring delocalizes the positive charge via resonance.

Answer 1

The Correct Option is A

Step 1: Check the Assertion.
Aromatic diazonium salts ($C_6H_5N_2^+Cl^-$) are stable enough to be used in synthesis at 0-5$^\circ$C, while aliphatic diazonium salts decompose almost instantly. Assertion is TRUE.
Step 2: Check the Reason.
In aromatic diazonium salts, the positive charge on nitrogen is delocalised into the benzene $\pi$-system via resonance. Aliphatic diazonium salts lack any $\pi$-system for such stabilisation. Reason is TRUE.
Step 3: Does R explain A?
The resonance stabilisation described in R is precisely the reason aromatic diazonium salts persist longer than aliphatic ones. R correctly and directly explains A.
Step 4: Conclusion.
Both A and R are true, and R is the correct explanation of A.
\[ \boxed{\text{Both true; R is the correct explanation}} \]