Why is Methanol more acidic than Ethanol eventhough the conjugate base of Ethanol is stabilised by hyperconjugation?
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1$\begingroup$ What hyperconjugation is this? $\endgroup$– Haha HahahaJan 16, 2020 at 7:02
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$\begingroup$ Means?. I only know one kind of hyperconjugation $\endgroup$– Equation_CharmerJan 16, 2020 at 8:17
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$\begingroup$ But shouldn't u consider -H effect for stability of anions ...but that's the not the case here, there is no -H group...how can u compare based on that? $\endgroup$– MuskaanJan 16, 2020 at 13:05
1 Answer
Hyperconjugation is seen when there is a vacant p orbitals to where Alpha hydrogens can relocate their electrons.Conjugate base of ethanol does not have any vacant p orbitals. So hyperconjugation doesn't play any role in stabilization of conjugate base.
The stability of alkoxide ions in solution is determined by how much they get solvated in aqueous solutions.Smaller ions are more solvated than bigger ions,thus methoxide being a smaller ion is more solvated than ethoxide.Solvation of charged ions provide them stability.Thus methoxide have more stability in aqueous solution than ethoxide.Thus explaining why ethanol is less acidic than methanol aqueous solution.