The reaction involves two different carbonyl compounds: Benzaldehyde ($C_6H_5CHO$) and Acetophenone ($C_6H_5COCH_3$).

1. Benzaldehyde lacks $\alpha$-hydrogens and cannot undergo self-aldol condensation (it would undergo Cannizzaro in concentrated base, but dilute base is specified).
2. Acetophenone possesses $\alpha$-hydrogens and can form an enolate ion in the presence of dilute NaOH.
3. When these two react, the enolate generated from acetophenone attacks the electrophilic carbonyl carbon of benzaldehyde.
4. Since the condensation occurs between two different carbonyl compounds (one aldehyde and one ketone), it is termed a Cross Aldol Condensation (specifically, a Claisen-Schmidt condensation).