Question

Which of the following Grignard Reagent will be used to prepare the given alcohol when treated with methanal ?

• A. \(CH_3MgBr\)
• B. [structure (B) - image pending]
• C. [structure (C) - image pending]
• D. [structure (D) - image pending]

Hint:

A Grignard reagent (\(R-MgBr\)) adds to methanal (formaldehyde, HCHO). After hydrolysis it gives a primary alcohol \(R-CH_2OH\), where the new alcohol has one more carbon than the alkyl group of the Grignard reagent.

Answer 1

The Correct Option is A

Step 1: Recall the reaction.
A Grignard reagent \(R-MgBr\) adds to methanal (formaldehyde, HCHO). After hydrolysis it gives a primary alcohol \(R-CH_2OH\).

Step 2: Note the carbon count.
The product alcohol has one carbon more than the alkyl group \(R\) of the Grignard reagent, because the carbon of methanal is added.

Step 3: Work backward from the target alcohol.
Remove the \(-CH_2OH\) part of the required alcohol. The leftover group tells us which \(R-MgBr\) is needed.

Step 4: Identify R.
For the given target, the leftover group is methyl, so the Grignard reagent is \(CH_3MgBr\).

Step 5: Conclusion.
\(CH_3MgBr\) reacting with HCHO followed by hydrolysis gives the desired alcohol.

\[ \boxed{CH_3MgBr} \]