Acetophenone and benzaldehyde are warmed with NaOH in ethanol until dehydration is complete to give P. P is then shaken with exactly one mole of $H X_{2}$ over Pd/C at room temperature to give Q. Q is

Answer: B

Claisen-Schmidt condensation gives P, chalcone

C X_{6} H X_{5} CH = CHCOC X_{6} H X_{5}

. With one mole of

H X_{2}

over Pd/C, the isolated C=C is reduced much faster than the aryl ketone or the rings. Q is

C X_{6} H X_{5} CH X_{2} CH X_{2} COC X_{6} H X_{5}

, 1,3-diphenylpropan-1-one.