Question

`CH_(2)=CH^(-)` is a better nucleophile than `HC -= C^(-)`. Explain.

Answer 1

In `H_(2)C = CH^(-)`, the carbon atom carrying the -ve charge is `sp^(2)` hybridized while in `HC -= C^(-)`, the carbon atom carrying the -ve charge is sp-hybridized. Since a `sp^(2)`-hybridized carbon is less electronegative than a sp-hybridized carbon, therefore, `H_(2)C = CH^(-)` is a better nucleophile than `HC -= C^(-)`.