Question

Identify the alcohol obtained when aldehyde other than formaldehyde is treated with Grignard's reagent followed by hydrolysis.

• A. Primary alcohol
• B. Secondary alcohol
• C. Tertiary alcohol
• D. Ketone

Hint:

Formaldehyde gives a primary alcohol, other aldehydes give secondary alcohols and ketones give tertiary alcohols.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A Grignard reagent \(\text{R-MgX}\) adds across the C=O bond. The R group goes to carbon and \(\text{MgX}\) goes to oxygen. Hydrolysis then gives the alcohol.

Step 2: Detailed Explanation:
For an aldehyde \(\text{R'CHO}\):
\[ \text{R'CHO} + \text{RMgX} \to \text{R'CH(R)OMgX} \xrightarrow{\text{H}_2\text{O}} \text{R'CH(OH)R} \]
The carbon bearing the OH group is now attached to two carbon groups (R and R') and one hydrogen. An alcohol with two alkyl groups on the carbinol carbon is a secondary alcohol.

Step 3: Compare with other carbonyls.
Formaldehyde HCHO gives a primary alcohol. A ketone gives a tertiary alcohol. So an aldehyde other than formaldehyde gives a secondary alcohol, option (B). A ketone (D) is not an alcohol.

Final Answer:
The product is a secondary alcohol. \[ \boxed{\text{Secondary alcohol}} \]