[JEE 2012]

Solution

Since, there are 3 α hydrogen atoms in CH₃CHO, we can expect 3 Aldol Condensation (AC) reactions. We need to verify this arriving at the final product mentioned.

Starting with the first enolate anion,

The product above can give another enolate anion as it has 2 α hydrogen atoms causing another Aldol reaction,

The product above can give another enolate anion as there still is one α hydrogen causing yet another Aldol reaction,

There is no more alpha hydrogen present in the product above and hence there is no more Aldol reaction possible.

Answer: C