Give reasons in two or three sentences only for the following: Phenul group is known to exert negative inductive effect, but each phenyl ring in biphenyl `(C_(6)H_(5)-C_(6)H_(5))` is more reactive than benzene towards electrophilic substitution.

The order of reactivity of the following compounds C_(6)H_(5)CH_(3) C_(6)H_(5)CH_(2)CH_(3) towards electrophilic substritution will be :

C_(6)H_(5)Cl is "less" // "more" reactive than C_(6)H_(11)Cl .

C_(6)H_(5)Cl is "less" // "more" reactive than C_(6)H_(11)Cl .

Assertion : Oxidation of toluene as well as ethyl benzene with KMnO_(4) gives benzoic acid. Reason : Both toluene and ethyl benzene are more reactive than benzene towards electrophilic substitution reactions.

The following reaction, +C_(6)H_(5)CO_(3)H . Gives :

Benzil, C_(6)H_(5)COCOC_(6)H_(5) , on heating with aqueous KOH and subsequent acidification gives

Benzene and other aromatic hydrocarbons, though contain pi -bonds, yet they behave as saturated hydrocarbons. They are stable because of delocalisation of cloud. These undergo electrophilic substitution reactions as : C_(6)H_(5)-H + YZ to C_(6)H_(5)Y +HZ The reactivity of aromatic hydrocarbons towards electrophilic substitution depends upon the electron density in the benzene ring In the reaction of C_(6)H_(5)Y , the major product is m-isomer. The group Y may be

Benzene and other aromatic hydrocarbons, though contain pi -bonds, yet they behave as saturated hydrocarbons. They are stable because of delocalisation of cloud. These undergo electrophilic substitution reactions as : C_(6)H_(5)-H + YZ to C_(6)H_(5)Y +HZ The reactivity of aromatic hydrocarbons towards electrophilic substitution depends upon the electron density in the benzene ring The electrophile in sulphonation of benzene is