Question

Why is ethanol a stronger acid than tert-butanol in solution?

Answer 1

HA <-----> H⁺  + A^-

when ethanol behaves as an acid the corresponding conjugate base formed is ethoxide ion C2H5O^-

but when t-butoxide loses a proton, it forms t-butoxide anion (CH3)3C O^- as the conjugate base.

The t-butoxide ion has 3 electron donating methyl groups on the carbon attached to the negatively charged oxygen thus destabilizing the anion and the acid-base equilibrium shifts towards left side (undissociated t-butanol).

while in ethoxide ion only one electron donating methyl group is on the carbon attached to oxide ion, thus it is relatively more stable than t- butoxide ion.