Question

Observe the following reaction sequence:
\[ \text{C}_4\text{H}_8 \xrightarrow{\text{HCl}} \text{C}_4\text{H}_7\text{Cl} \xrightarrow{\text{NH}_3} \text{C}_4\text{H}_9\text{NH}_2 \xrightarrow{\text{NaNO}_2 + \text{HCl}} \text{C}_4\text{H}_9\text{OH} \] Which of the following is the correct structure for A, B, and C?

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

In a diazotization reaction, an amine is converted to a diazonium ion, which is then replaced by a hydroxyl group to form an alcohol.

Answer 1

The Correct Option is D

To solve this sequence of reactions, we will analyze each step:

1. Step 1: Addition of HCl to C₄H₈
   Here, C₄H₈ could be butene, a linear or branched alkene. The addition of HCl will typically follow Markovnikov's rule, where the hydrogen atom attaches to the carbon with more hydrogen atoms, and the chlorine attaches to the more substituted carbon resulting in 2-chlorobutane.
2. Step 2: Reaction with NH₃
   The chlorinated compound (2-chlorobutane) then undergoes a substitution reaction with NH₃ to form an amine, specifically butan-2-amine.
3. Step 3: Reaction with NaNO₂ and HCl
   The amine reacts with NaNO₂ and HCl to form a diazonium salt, which further undergoes hydrolysis to produce the corresponding alcohol, which is butan-2-ol.

The correct structure sequence is:

• (A) = 2-butene
• (B) = 2-chlorobutane
• (C) = butan-2-amine

Thus, the correct option is 4, as given in the options.