Q.Write the structure of the major product of the aldol condensation of benzaldehyde with acetone.

Step 1. Benzaldehyde has NO alpha-hydrogen of its own (its 'alpha-position' is the aromatic ring, which cannot be deprotonated by dilute base the way an aliphatic methyl group can), so it cannot self-condense.

Step 2. Acetone, CH3-CO-CH3, DOES have alpha-hydrogens on both of its methyl groups; in dilute NaOH, one of those alpha-carbons is deprotonated to give the resonance-stabilised enolate carbanion, CH2=C(O-)-CH3 (equivalently -:CH2-CO-CH3).

Step 3. This acetone-derived carbanion attacks benzaldehyde's electrophilic carbonyl carbon, forming the new C-C bond and, after protonation, the beta-hydroxy ketone (aldol) intermediate, C6H5-CH(OH)-CH2-CO-CH3. …

Recognise that benzaldehyde (no alpha-hydrogen) can only act as the electrophile, while acetone (which has alpha-hydrogens) supplies the attacking enolate carbanion -- this specific pairing is the Cl …

• Drawing the SELF-aldol product of acetone alone (mesityl oxide-type structure), forgetting that benzaldehyde is present specifically to act as the el …