So everywhere that I've read, there's the reasoning that the acidity of a compound is determined by how stable the conjugate base is, this should be the same for alcohols too, but on Chemistry LibreTexts there's an article which says otherwise, and the reason being that if the electron donating ie. inductive effect was responsible for this then we would have obsereved the same acidity order of alcohols in the gaseous phase too, where the relative acidity trend is quite opposite of what it is in solution.

The rationale behind this as is given in the article is:

Polarizibility almost completely accounts for the trend in gas-phase acidities. As the size of the substituent increases, the acid becomes stronger due to the ability for the charge to be distributed over a larger volume, thereby reducing the charge density and, consequently, the Coulombic repulsion.In solution, however, the ions can be stabilized by solvation, and this is what leads to the inversion of acidity ordering. Brauman and Blair showed that smaller ions are better stabilized by solvation, which is consistent with the Born equation.

Now there are these two things that are not clear to me

  1. If the substituents are almost similiar in size such that the charge almost gets a similiar size to spread, let's say they are amine and methyl groups on the beta carbon, will we then take the inductive effect into account to determine the acidity of the alcohol?

  2. Why is this then only applicable to alcohols? Why not the same reasoning for determing basicity and acidity of other functional groups?

  • 1
    $\begingroup$ That's just a thing to show whys and hows of "inductive effect" of alkyl groups vs hydrogen. See, carbon is actually more electronegative then hydrogen, and yet ethanol is weaker acid then water in aqueous solution. In gas phase, not so much. And, yeah, polarisability is probably more adequately correlated parameter for gas phase in such situation. $\endgroup$
    – Mithoron
    Aug 10 at 17:27
  • $\begingroup$ @Mithoron Could you expand on the whys and hows, I'm not sure how electronegativity and inductive effect correlate. $\endgroup$ Aug 11 at 6:16

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