Question

Identify the compound obtained when ethyl methyl ketone is treated with \(\text{CH}_3\text{MgBr}\) and hydrolyzed.

• A. \((\text{CH}_3)_3\text{C}-\text{OH}\)
• B. \(\text{C}_2\text{H}_5-\overset{\overset{\text{CH}_3}{|}}{\underset{\underset{\text{CH}_3}{|}}{\text{C}}}-\text{OH}\)
• C. \((\text{C}_2\text{H}_5)_3\,\text{C}-\text{OH}\)
• D. \(\text{CH}_3-\overset{\overset{\text{C}_2\text{H}_5}{|}}{\underset{\underset{\text{C}_2\text{H}_5}{|}}{\text{C}}}-\text{OH}\)

Hint:

A ketone with a Grignard reagent gives a tertiary alcohol after hydrolysis.

Answer 1

The Correct Option is B

Step 1: Count Groups:
The carbinol carbon of the product carries the groups already on the ketone carbon (CH$_3$ and C$_2\text{H}_5$) plus the new CH$_3$ from the Grignard reagent, along with OH.

Step 2: Result:
So the carbon has two methyl groups, one ethyl group and OH, which is 2-methylbutan-2-ol, option (B).

Step 3: Others:
Option (A) lacks the ethyl group and options (C) and (D) have too many ethyl groups.

Final Answer:
Option (B). \[ \boxed{\text{(B) } \text{C}_2\text{H}_5\text{C}(\text{CH}_3)_2\text{OH}} \]