Which one of the following gives the most stable diazonium salt ?
(a) CH3-CH2-CH2-NH2
(b) p-methylan

Q: Why are aliphatic diazonium salts unstable?

Aliphatic diazonium salts lack the resonance stabilization provided by an aromatic ring. Consequently, they readily decompose to form carbocations and nitrogen gas.

Q: How does the methyl group stabilize the diazonium salt?

The methyl group is an electron-donating group. It releases electron density into the aromatic ring through the $+I$ effect and hyperconjugation, which helps to disperse the positive charge on the diazonium group, increasing its stability.

Question

Which one of the following gives the most stable diazonium salt ?

Options:

(A) $CH_3-CH_2-CH_2-NH_2$

(B) p-methylaniline

(C) $CH_3-CH(CH_3)-NH_2$

(D) N-methylaniline

Sigma Percentile · Accepted Answer

### Diazotization Reaction
Primary amines react with $NaNO_2$ and $HCl$ to form diazonium salts. This reaction is known as diazotization.

### Stability of Diazonium Salts
Aromatic diazonium salts are generally more stable than their aliphatic counterparts. This increased stability is attributed to the resonance stabilization provided by the aromatic ring, which can delocalize the positive charge on the nitrogen atom.

### Effect of Substituents
The presence of electron-donating groups on the aromatic ring further enhances the stability of the diazonium salt. These groups, such as the methyl group ($-CH_3$), release electron density into the ring through the $+I$ (inductive) and hyperconjugation effects. This increased electron density helps to disperse the positive charge on the diazonium group, thereby stabilizing the entire molecule. Therefore, p-methylaniline forms the most stable diazonium salt among the given options.

Animated Solution for Chemistry - Organic Compounds Containing Nitrogen: Which one of the following gives the most stable diazonium salt ?

Select Answer:

Visualized Solution

$Diazotization Reaction$

$Stability of Diazonium Salts$

$Effect of Substituents$

The Sigma Insight: Aromatic Amines

Diazotization Reaction Primary amines react with $N a N O_{2}$ and $H C l$ to form diazonium salts

Stability of Diazonium Salts Aromatic diazonium salts are generally more stable than their aliphatic counterparts

Effect of Substituents The presence of electron-donating groups on the aromatic ring further enhances the stability of the diazonium salt