Aliphatic nucleophilic substitution mainly takes place by two mechanisms (i.e) SN^1 & SN^2Primary halides mainly undergo by SN^2mechanism and are favourable in polar aprotic solvents. SN^1 reactions takes place mainly by tertiary halide and are more favourable in polar protic solvents, In case of tertiary halides, E_1comes competition to SN^1 reaction. Keeping in view of these general points, answer the following questionsWhich of the following reactions, the reactions takes place by SN^1mechanism mainly.

Aliphatic nucleophilic substitution mainly takes place by two mechanis

1.	Aliphatic nucleophilic substitution mainly takes place by two mechanisms (i.e) SN^1 & SN^2Primary halides mainly undergo by SN^2mechanism and are favourable in polar aprotic solvents. SN^1 reactions takes place mainly by tertiary halide and are more favourable in polar protic solvents, In case of tertiary halides, E_1comes competition to SN^1 reaction. Keeping in view of these general points, answer the following questionsWhich of the following reactions, the reactions takes place by SN^1mechanism mainly.
Answer» `CH_3CH_2CH_2Br` SOLUTION :FORMATION stable carbocation is the major REQUIRED condition, BENZYL carbocation is very stable dueto RESONANCE