Question

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

Answer 1

When acetylene is passed through red hot $Fe$ tube at $873K$, benzene is formed.
Benzene reacts with $CO+HCl$ in presence of a Lewis acid to formed benzaldehyde. This reaction is known as Gattermann Koch reaction.

Benzaldehyde has $7$ carbon atoms and all are $s{p}^2$ hybridized.