Which of the following statements are correct ?

Options

A. Polar protic solvents (e.g, `MeOH, EtOH`) form H-bonding to nucleophile and stabilise it, thus rate of `SN^2` reaction is decreased.
B. Polar aprotic solvents (e.g., `DMSO, DMF`) raise the energy of the nucleophile and thus the rate of `SN^2` is increased.

C. Reactivity of nucleophile in the presence of crown ether (solvent) is increased for `SN^1` and `SN^2` reactions.
D. Reactivity nucleophile in the presence of crown ether (solvent) is decreased for `SN^(1)` and `SN^(2)` reactions.

Answer

A, B, C