Out of HO^(-) or HS^(-) which one is (a) better nucleophile and (B) a better base ?

Out of HO^(-) or HS^(-) which one is (a) better nucleophile and (B) a

1.	Out of HO^(-) or HS^(-) which one is (a) better nucleophile and (B) a better base ?
Answer» Solution :(a) S is less electronegative than O, therefore, it can DONATE a pair of electrons more easily than O. Thus, `HS^(-)` is a BETTER nucleophile than `HO^(-)`. (b) Since O-H BOND is stronger than S-H bond, therefore `HO^(-)` has a GREATER tendency to accept a proton than `HS^(-)` and hence `HO^(-)` is a better BASE than `HS^(-)`.