Identify the structure of the final product (D) in the following sequence of reactions:

Total number of $$sp^2$$ hybridised carbon atoms in product D is _____.

The reaction sequence finally furnishes acetophenone, $$C_6H_5COCH_3$$, as product $$D$$.

Hybridisation check:
• The six ring-carbons of the benzene nucleus are all $$sp^2$$.
• The carbonyl carbon of the $$C=O$$ group is also $$sp^2$$.
• The three hydrogens on the methyl carbon come from an $$sp^3$$ carbon, so that carbon is not counted.

Hence the total number of $$sp^2$$-hybridised carbon atoms in product $$D$$ is $$6 + 1 = 7$$.

Answer: 7