Q102 / 180 · NEET 2026 (Cancelled) · Chemistry
The major product Z formed in the following sequence of reactions is :
$\text{C}_2\text{H}_6 \xrightarrow[\text{UV light}]{\text{Cl}_2} X \xrightarrow{\text{NH}_3} Y \xrightarrow[(\text{monochlorinated product})]{\text{(i) NaNO}_2/\text{HCl}\ \ \text{(ii) H}_2\text{O}} Z$
$\text{C}_2\text{H}_6 \xrightarrow[\text{UV light}]{\text{Cl}_2} X \xrightarrow{\text{NH}_3} Y \xrightarrow[(\text{monochlorinated product})]{\text{(i) NaNO}_2/\text{HCl}\ \ \text{(ii) H}_2\text{O}} Z$
- A$\text{C}_2\text{H}_5\text{NO}_2$
- B$\text{C}_2\text{H}_5-N=N-\text{OH}$
- Correct answerC$\text{C}_2\text{H}_5\text{OH}$
- D$\text{C}_2\text{H}_5\text{NH}_2$
Solution
Ethane undergoes free radical halogenation with chlorine in the presence of UV light to form ethyl chloride (X).
$\text{C}_2\text{H}_6 + \text{Cl}_2 \xrightarrow{\text{UV light}} \text{C}_2\text{H}_5\text{Cl} \ (X)$
Ethyl chloride reacts with ammonia via nucleophilic substitution to form ethylamine (Y).
$\text{C}_2\text{H}_5\text{Cl} + \text{NH}_3 \rightarrow \text{C}_2\text{H}_5\text{NH}_2 \ (Y)$
Ethylamine, being a primary aliphatic amine, reacts with nitrous acid ($\text{NaNO}_2 + \text{HCl}$) to form an unstable aliphatic diazonium salt, which decomposes to yield a carbocation. The carbocation reacts with water to form ethanol (Z).
$\text{C}_2\text{H}_5\text{NH}_2 \xrightarrow{\text{NaNO}_2/\text{HCl}} [\text{C}_2\text{H}_5\text{N}_2^{+}\text{Cl}^{-}] \xrightarrow{\text{H}_2\text{O}} \text{C}_2\text{H}_5\text{OH} \ (Z) + \text{N}_2 + \text{HCl}$
Thus, the major product Z is $\text{C}_2\text{H}_5\text{OH}$.
Answer: $\text{C}_2\text{H}_5\text{OH}$
$\text{C}_2\text{H}_6 + \text{Cl}_2 \xrightarrow{\text{UV light}} \text{C}_2\text{H}_5\text{Cl} \ (X)$
Ethyl chloride reacts with ammonia via nucleophilic substitution to form ethylamine (Y).
$\text{C}_2\text{H}_5\text{Cl} + \text{NH}_3 \rightarrow \text{C}_2\text{H}_5\text{NH}_2 \ (Y)$
Ethylamine, being a primary aliphatic amine, reacts with nitrous acid ($\text{NaNO}_2 + \text{HCl}$) to form an unstable aliphatic diazonium salt, which decomposes to yield a carbocation. The carbocation reacts with water to form ethanol (Z).
$\text{C}_2\text{H}_5\text{NH}_2 \xrightarrow{\text{NaNO}_2/\text{HCl}} [\text{C}_2\text{H}_5\text{N}_2^{+}\text{Cl}^{-}] \xrightarrow{\text{H}_2\text{O}} \text{C}_2\text{H}_5\text{OH} \ (Z) + \text{N}_2 + \text{HCl}$
Thus, the major product Z is $\text{C}_2\text{H}_5\text{OH}$.
Answer: $\text{C}_2\text{H}_5\text{OH}$
Hence, the correct answer is option: 'C'.