High School

How will you synthesize the following alcohol prepared by the reaction of a suitable Grignard reagent on methanal?

A. CH₃OH
B. CH₃CH₂OH
C. CH₃CHOH
D. CH₃CH₂CH₂OH

Answer :

Final answer:

To synthesize ethanol (CH₃CH₂OH) from methanal, a methyl Grignard reagent (CH₃MgBr) is reacted with methanal, which after hydrolysis produces ethanol. So, the correct option is b) CH₃CH₂OH.

Explanation:

To synthesize a primary alcohol such as ethanol (CH₃CH₂OH) from methanal (formaldehyde), we can use the following reaction with a suitable Grignard reagent:

CH₃MgBr (methylmagnesium bromide) + HCHO (methanal)
arr CH₃CH₂OH (ethanol)

In this reaction, the methyl Grignard reagent, which is a strong nucleophile, attacks the electrophilic carbon in the carbonyl group of methanal. The addition of the organomagnesium compound to methanal followed by hydrolysis yields ethanol as the primary alcohol product.