Which would undergo S_N1 reaction faster in the following pair?

• In the above question, molecule (A) is secondary halide and molecule (B) is a primary halide.

• We know that rate of S_N1 reaction follows the order 3°>2°>1°.

• This means that a tertiary halide undergoes S_N1 reaction more easily than a secondary halide.

• Thus molecule (B) undergoes S_N1 reaction faster than molecule (A).