Question

Consider the following chemical reaction.
$HC\equiv CH\underset{(2)CO+HCl/AlC{l}_3}{\overset{(1)\text{Red hot Fe tube,}873K}{\to }}$ Product
The number of $s{p}^2$ hybridized carbon atom(s) present in the product is ______.

Answer 1

Answer: 7

Pass the three molecules of ethyne through the red hot $Fe$ tube at $873K$. All the three molecules of ethyne undergo cyclic polymerization to form benzene. In Gattermann - Koch reaction, benzene is treated with carbon monoxide in acidic medium in presence of anhydrous aluminum chloride to give benzaldehyde.

All carbon atoms in benzaldehyde are $s{p}^2$ hybridised