$C_6H_5CHClC_6H_5$ is hydrolysed faster. (a) Hydrolysis of an alkyl halide is an example of nucleophilic substitution reaction. In case of aryl halides this follows the $S_N1$ pathway i.e., via the formation of carbocation. (b) $C_6H_5CH_2Cl$or benzyl chloride gives(c) Out of I & II, carbocation II is more stable. The reason is the presence of two phenyl rings attached to the carbon carrying the positive charge. (d) As a result, the delocalisation of the +ve charge is greater and the carbocation is more stable. Due to this, (II) is formed faster and the corresponding halide is hydrolysed with greater ease as compared to benzyl chloride.