Question

The product of following reaction is

• A. \( CH_3-CH_2-CH_2-CH_2-CH_2-OH \)
• B. \( CH_3-CH=CH-CH_2-CH_2-OH \)
• C. \( CH_3-CH_2-CH_2-CH_2-COOH \)
• D. \( CH_3-CH=CH-CH_2-COOH \)

Answer 1

The Correct Option is B

The given compound is CH₃–CH=CH–CH₂–CHO, an α,β-unsaturated aldehyde (4-pentenal).

Step 1: Reaction with LiAlH₄
Lithium aluminium hydride (LiAlH₄) is a strong reducing agent. It reduces aldehydes (–CHO) to primary alcohols (–CH₂OH) but does not reduce C=C double bonds.

The reduction of CH₃–CH=CH–CH₂–CHO gives CH₃–CH=CH–CH₂–CH₂–OH.

Step 2: Acidic workup with H₃O⁺ 
This step neutralizes the reaction mixture and protonates the alkoxide intermediate to yield the final alcohol.

Therefore, the overall reaction is:

CH₃–CH=CH–CH₂–CHO ⟶ (i) LiAlH₄ / (ii) H₃O⁺ ⟶ CH₃–CH=CH–CH₂–CH₂–OH

Hence, the product is: 
CH₃–CH=CH–CH₂–CH₂–OH