[Vishal]

Exchange reaction between biphenyl-methyl chloride and radio chlorine (LiCl^*) in dimethyl foramide occurs by simultaneous nucleophilic substitution (S_N1 and S_N2) mechanism. Can anyone please provide the mechanism and is there any more example for this type?

Nucleophilic substitution is the reaction of an electron pair donor (the nucleophile, Nu) with an electron pair acceptor (the electrophile). An sp3-hybridized electrophile must have a leaving group (X) in order for the reaction to take place.