The correct order of leaving group ability in a nucleophilic substitution reaction is

Options

A. `Br^(-) gt Cl^(-) gt CH_(3) CO_(2)^(-) gt HO ^(-) gt H^(-)`
B. `H^(-) gt OH^(-) gt CH_(3) CO_(2)^(-) gt Cl^(-) gt Br^(-)`
C. `Br^(-) gt CH_(3)CO_(2)^(-) gt Cl^(-) gt OH^(-) gt H^(-)`
D. `CH_(3) CO_(2)^(-) gt Br^(-) gt Cl^(-) gt OH^(-) gt H^(-)`

Answer

A

Explanation

A leaving group is a molecular fragment that departs with a pair of electrons in heterolytic bond cleavage. The weaker the base, the better the leaving group.
Br- and Cl- are both excellent leaving group with Br- being better than `Cl- CH_(3) COO`-are moderate
leaving group. OH- is a strong base hence it is a poor leaving group. H- is an extremely poor leaving group as it a very strong base