Hello,

1. The chemical reaction between Benzaldehyde and Acetone is also known as Aldol Reaction.

2. The major product formed in the reaction is dibenzalacetone.

The reaction takes place as follows:

Acetone has α-hydrogens (on both sides) and thus can be deprotonated to give a nucleophilic enolate anion. The aldehyde carbonyl is much more electrophilic than that of a ketone, and therefore reacts rapidly with the enolate. The alkoxide produced is protonated by solvent, giving a β-hydroxyketone, which undergoes base-catalyzed dehydration. The elimination process is particularly fast in this case because the alkene is stabilized by conjugation to not only the carbonyl but also the benzene.

3. The molecular formula of dibenzalacetone is C17H14O and molecular mass is 234.29 u.

The molecular mass of carbon is 12.0107 u.

So, Mass percentage of carbon = ( 17 x 12.0107 ) x 100 / 234.29 = 87%

Hence, mass percentage of carbon in major product in reaction between benzaldehyde and acetone, i.e., dibenzalacetone is 87%

Best Wishes.