Rate of the reaction.

is fastest when `Z` is

The reaction is fastest when X is

Rate of the reaction of fastest when 'Z' is R-overset(O)overset(||)(C)-Z+Nu^(-) rarr R - overset(O)overset(||)(C)-Nu + Z^(-)

The reaction , is fastest when X is

Rate of the reaction is faster when Z is :

The reaction, is fastest when X is :

The reaction, is fastest when X is :

The reaction is fastest when X is :

SN^1 reaction is fastest in