Basicity of ethoxide vs. hydroxide ions

Steps:

• Compare pKa values: water (15.7) is more acidic than ethanol (15.9), so OH⁻ is weaker base than CH₃CH₂O⁻.
• Conjugate base strength: weaker acid yields stronger conjugate base, confirming ethoxide as stronger base.
• Electron effects: ethyl group donates electrons inductively, raising electron density on oxygen in ethoxide.
• Reaction implication: stronger base aligns with slower sodium-ethanol reaction vs. water.

Why B is correct:

• Inductive effect: electron-donating ethyl group increases electron density on oxygen (Pauling electronegativity), making ethoxide more willing to accept protons than OH⁻.

Why the others are wrong:

• A: Water reaction is faster; higher acidity of water facilitates quicker deprotonation by sodium.
• C: Charge in ethoxide is localized on oxygen; no conjugation or resonance for delocalization.
• D: Ethanol is less acidic (higher pKa), so harder to deprotonate than water.

Final answer: B