MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The rate of an SN ^2 reaction is inversely proportional to the steric hindrance around the carbon atom bearing the leaving group. The order of reactivity of alkyl halides towards SN ^2 mechanism is: Methyl halide > 1^ alkyl halide > 2^ alkyl halide > 3^ alkyl halide. Among the given options: CH _3 -Br is a methyl halide. CH _3 -CH _2 -Br is a 1^ alkyl halide. ( CH _3)_2 CH-Br is a 2^ alkyl halide. ( CH _3)_3 C-Br is a 3^ alkyl halide. Since CH _3 -Br has the least steric hindrance, it is hydrolyzed most rapidly by the SN ^2 mechanism. Answer: CH _3 -Br