Question

Consider thiol anion $\left(R S^{\ominus}\right)$ and alkoxy anion $\left(R O^{\ominus}\right)$. Which of the following statements is correct?

• A. $R S^{\ominus}$ is less basic but more nucleophilic than $R O^{\ominus} .$
• B. $R S^{\ominus}$ is more basic and more nucleophilic than $R O^{\ominus}$.
• C. $RS^\ominus$ is more basic but less nucleophilic than $RO^\ominus$.
• D. $RS^\ominus$ is less basic and less nucleophilic than $RO^\ominus$.

Answer 1

Answer: (A)

$R S^{\ominus}$ is more nucleophilic than $R-O^{\ominus}$ due to larger size of orbitals and polarization but $R S^{\ominus}$ is less basic than $R-O^{\ominus}$ as the negative charge get stabilized due to larger size of sulphur atom.