Question

Which of the following does not possess alpha hydrogen?

• A. Acetaldehyde
• B. Formaldehyde
• C. Acetone
• D. Phenyl acetaldehyde

Answer 1

The correct option is B Formaldehyde

The chemical formula of formaldehyde is $HCHO$ which has a single carbon.

As there is no $\alpha$ carbon, there is no $\alpha$ hydrogen.

The chemical formula of acetaldehyde, acetone and phenyl acetaldehyde are $C{H}_{3}CHO$, $C{H}_{3}COC{H}_3$ and $PhC{H}_{2}CHO$ respectively.

Thus, all these three possess an alpha hydrogen.

Option B is correct.