Questions: Select the single best answer. Identify the stronger nucleophile in the following pair of anions. HO- or Cl- in a polar aprotic solvent. HO- Cl-

Solution Steps

In polar aprotic solvents, nucleophilicity is primarily determined by the basicity of the nucleophile. This is because polar aprotic solvents do not solvate anions well, allowing the nucleophile to be more reactive. Basicity is a measure of how well a species can donate a pair of electrons, which is a key factor in nucleophilicity.

The hydroxide ion ($\mathrm{HO}^{-}$) is a stronger base than the chloride ion ($\mathrm{Cl}^{-}$). This is because oxygen is less electronegative than chlorine, making $\mathrm{HO}^{-}$ more willing to donate its lone pair of electrons compared to $\mathrm{Cl}^{-}$.

Since $\mathrm{HO}^{-}$ is a stronger base than $\mathrm{Cl}^{-}$, it is also a stronger nucleophile in a polar aprotic solvent. The lack of solvation in such solvents allows $\mathrm{HO}^{-}$ to effectively use its electron pair for nucleophilic attacks.

Final Answer