Chemistry - Halogen Derivative Question with Solution | TestHub

The given species ${\text{CH}}_3^{-}$, ${\text{NH}}_2^{-}$, ${\text{OH}}^{-}$, and ${\text{F}}^{-}$ have donor atoms belonging to the same period (Period 2) of the periodic table.

Across a period from left to right, the electronegativity of the atoms increases in the order $\text{C}<\text{N}<\text{O}<\text{F}$.

A more electronegative atom holds its lone pair of electrons more tightly, making it less available for donation to an electrophile. Therefore, nucleophilicity decreases as electronegativity increases.

The order of nucleophilicity is ${\text{CH}}_3^{-}>{\text{NH}}_2^{-}>{\text{OH}}^{-}>{\text{F}}^{-}$.

Thus, ${\text{CH}}_3^{-}$ has the highest nucleophilicity.

Answer: ${\text{CH}}_3^{-}$