Question

Which among the following is an aromatic aldehyde ?

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

In an aromatic aldehyde the CHO group is bonded directly to the benzene ring.

Answer 1

The Correct Option is D

Step 1: What to look for
Find the structure in which the carbonyl carbon of the aldehyde is a direct neighbour of an aromatic ring carbon.

Step 2: Scan the four drawings
Drawing (A): ring, then one $\text{CH}_2$, then CHO, so there is a gap of one carbon. Drawing (B): ring, then a $\text{CH=CH}$ unit, then CHO, so there is a gap of two carbons. Drawing (C): no benzene ring, only a saturated six-membered ring.

Step 3: Drawing (D)
The ring carbon bears the CHO group itself, with a methyl group on the adjacent ring carbon. Here the CHO is conjugated with the ring, as in benzaldehyde.

Step 4: Conclusion
Only (D) places -CHO directly on the benzene ring, so it is the aromatic aldehyde in the usual sense.

Final Answer:
Option (D) has CHO directly on the benzene ring. This is option (D). \[ \boxed{\text{(D) }\text{2-Methylbenzaldehyde}} \]