Give reasons for the following: (a) Chlorine is ortho/para directing in electrophilic aromatic substitution reactions, though chlorine is an electron…

Because of the stabilisation of intermediate carbocation through resonance. / Through resonance, chlorine tends to stabilize the carbocation and the effect is more pronounced at ortho- and para- positions.

Because mixture contains two enantiomers in equal proportions resulting in Zero Optical Rotation. / Due to the external compensation of equal percentage of (+) and (-) forms resulting in Zero Optical Rotation.

Because of the resonance stabilization of allyl carbocation.