Question

A Grignard reagent (X) on reaction with carbonyl compound (Y) followed by hydrolysis gave Z. Z reacts with conc. HCl at room temperature. X and Y respectively are

• A. \( \text{CH}_3\text{MgBr}, \text{CH}_3\text{CH}_2\text{CHO} \)
• B. \( \text{CH}_3\text{MgBr}, \text{CH}_3\text{COCH}_3 \)
• C. \( \text{CH}_3\text{CH}_2\text{CH}_2\text{MgBr}, \text{HCHO} \)
• D. \( \text{CH}_3\text{CH}_2\text{MgBr}, \text{CH}_3\text{CHO} \)

Hint:

Grignard reagents are strong nucleophiles and react with carbonyl compounds to form alcohols, which can further react with acids to undergo elimination.

Answer 1

The Correct Option is B

Step 1: Understanding Grignard Reaction with Carbonyl Compounds

- Grignard reagents react with carbonyl compounds to form alcohols after hydrolysis.

- The choice of carbonyl compound determines the type of alcohol formed.
Step 2: Reaction of CH$_3$MgBr with CH$_3$COCH$_3$
- Methyl magnesium bromide (\( \text{CH}_3\text{MgBr} \)) reacts with acetone (\( \text{CH}_3\text{COCH}_3 \)), forming a tertiary alcohol.
- Hydrolysis yields the final product Z.
Step 3: Reaction of Z with Conc. HCl
- The tertiary alcohol formed undergoes elimination in the presence of concentrated HCl, leading to the final product.