Consider thiol anion `(RS^(Theta))` and alkoxy anion `(RO^(Theta))`. Which of the following statements is correct?

Options

A. `RS^(Theta)` is less basic and less nucleophilic than `RO^(Theta)`
B. `RS^(Theta)` is less basic but more nucleophilic than `RO^(Theta)`
C. `RS^(Theta)` is more basic and more nucleophilic than `RO^(Theta)`
D. `RS^(Theta)` is more basic but less nucleophilic than `RO^(Theta)`

Answer

B

Explanation

Nucleophilic strength depends on the electronegativity of the atom. Lower the electrongetivity of an atom, larger the nucleophilic strength of an atom and more readily it will donate electrons to the electrphilic (`e^(-)` deficient) species. Since, electronegativity decreases down the group, thus nuclophilic strength increases down the group. Hence `RS`-is more nucleophilic than `RO^(-)` due to less electronagativity of `S` than `O`. On the other hand, basic strength of an atom depends upon the tendency to accept a proton more readily. Since, `O-H` bond is longer than `S-H` bond, thus `RS^(-)`. thus, basic strength of the central atom decreases down the group. Hence, `RS^(-)` is more nucleophilic but less basic than `RO^(-)`