Question

the order of reactivity of alkyl halide towards Sn2 is 1° halide>2° halide>3° halide and for Sn1 mechanism is 3° halide>2° halide>1° halide. Justify.​

Answer 1

Answer:

Reactivity of alkyl halide is dictated by the substitution of the

carbon bearing the halogen

primary (1°) : one alkyl substituent

secondary (2°) : two alkyl substituents

tertiary (3°) : three alkyl substituents

The SN1 Mechanism

The nucleophile does not appear in the rate equation – changing

the nucleophile concentration does not affect the rate of the

reaction.

SN1 – Substitution, Nucleophilic, unimolecular (1st order)

The SN2 Mechanism

Second-order reaction (bimolecular) – the rate is dependent on

the concentration of both reactants (nucleophile and electrophile)

If [OH-

] is doubled, then the reaction rate is doubled

If [CH3-Br] is doubled, then the reaction rate is doubled

SN2 – Substitution, Nucleophilic, bimolecular (2nd order)