Import Question JSON

$\text{Hint: RS}^- \text{ is more stable than RO}^-.$ $\text{Weak acid has strong conjugate base or vice versa.}$ $\text{The conjugate base of ROH is RO}^- \text{ and conjugate base of RSH is RS}^-.$ $\text{The conjugate base of RSH is more stable than conjugate base of ROH because sulphur can stabilize the negative charge more easily than oxygen.}$ $\text{Oxygen is more electronegative than sulphur hence, it will not easily share its electron with electrophile.}$ $\text{Hence, RS}^- \text{ is less basic but more nucleophilic than RO}^-.$ $\text{Nucleophilic strength depends on the electronegativity of the atom.}$ $\text{Lower the electronegativity of an atom, larger the nucleophilic strength of an atom and more readily it will donate electrons to the electrophilic (e- deficient) species.}$ $\text{Since, electronegativity decreases down the group, thus nucleophilic strength increases down the group,}$ $\text{Hence, RS}^- \text{ is more nucleophilic than RO}^- \text{ due to less electronegativity of S than O.}$ $\text{On the other hand, basic strength of an atom depends upon the tendency to accept a proton more readily.}$ $\text{Since, O-H bond is longer than S-H bond, thus, RO}^- \text{ has a greater tendency to accept a proton than RS}^-.$ $\text{Hence, RO}^- \text{ is a stronger base than RS}^-.$ $\text{Thus, basic strength of the central atom decreases down the group.}$ $\text{Hence, RS}^- \text{ is more nucleophilic but less basic than RO}^-.$