Question

Identify the aldehyde from following so that the aldehydic group is NOT attached with any \(sp^3\) hybrid 'c' atom.

• A. Methanal
• B. Ethanal
• C. 2-Methyl Propanal
• D. Propanal

Hint:

Only formaldehyde has the CHO group attached to hydrogen instead of a carbon.

Answer 1

The Correct Option is A

Step 1: Idea:
Look at what sits next to the carbonyl carbon in each aldehyde.

Step 2: Scan:
Ethanal, propanal and 2-methylpropanal each have an alkyl group, whose bonded carbon uses four single bonds, so it is $sp^3$. Methanal has only hydrogen atoms there.

Step 3: Answer:
Option (A).

Final Answer:
Option (A), methanal. \[ \boxed{\text{(A) Methanal}} \]