Q28 / 150 · MHT CET 2026 (19 April Shift 1) · Chemistry
Identify the aldehyde from following so that the aldehydic group is NOT attached with any $sp^3$ hybrid 'c' atom.
- Correct answerAMethanal
- BEthanal
- C2-Methyl Propanal
- DPropanal
Solution
Methanal is $H-CHO$. The aldehydic group ($-CHO$) is attached to a hydrogen atom, not to any carbon atom. Therefore, it is not attached to any $sp^3$ hybridized carbon atom.
Ethanal is $CH_3-CHO$. The $-CHO$ group is attached to a methyl group, which contains an $sp^3$ hybridized carbon atom.
2-Methylpropanal is $(CH_3)_2CH-CHO$. The $-CHO$ group is attached to a $CH$ group, which is an $sp^3$ hybridized carbon atom.
Propanal is $CH_3-CH_2-CHO$. The $-CHO$ group is attached to a $CH_2$ group, which is an $sp^3$ hybridized carbon atom.
Thus, methanal is the only aldehyde among the given options where the aldehydic group is not attached to an $sp^3$ hybridized carbon atom.
Ethanal is $CH_3-CHO$. The $-CHO$ group is attached to a methyl group, which contains an $sp^3$ hybridized carbon atom.
2-Methylpropanal is $(CH_3)_2CH-CHO$. The $-CHO$ group is attached to a $CH$ group, which is an $sp^3$ hybridized carbon atom.
Propanal is $CH_3-CH_2-CHO$. The $-CHO$ group is attached to a $CH_2$ group, which is an $sp^3$ hybridized carbon atom.
Thus, methanal is the only aldehyde among the given options where the aldehydic group is not attached to an $sp^3$ hybridized carbon atom.
Hence, the correct answer is option: 'A'.