Electronic Displacement Effects - Problem 5

Description:

Problem − Arrange the following in the order of increasing stability.

CH₃CH₂^-, HC ≡ C⁻, CH₂ = CH^-

Solution − The order of increasing stability.

• Carbanions are stabilized by electron-withdrawing groups which decrease the electron density on the carbon atom.

• Electronegativity: sp > sp² > sp³

• The electron donating methyl group in CH₃CH₂⁻ destabilizes the carbanion by increasing the electron density on the carbon atom via +I effect.

• sp² carbonion is more stable than Ch₃CH₂^- however, less stable as compared to HC ≡ C⁻ due to the higher electron withdrawing ability of sp hybridization state.