# pKa and pKb in solvents other than water

I know that when you have aqueous solutions, then the pKa and the pKb are linked to each other (pKa + pKb = 14). Is there an equivalent relationship between pKa and pKb in non aqueous environments? I'm currently looking at a paper where they have measured pKb values in glacial acetic acid (https://pubs.acs.org/doi/epdf/10.1021/ic50084a055), but I'm interested in finding the pKa values for a different set of compounds in glacial acetic acid. Thank you.

Bruckenstein and Kolthoff give some values in the abstract, which is available in the free preview. Notable among acids: perchloric acid, $$pK_a=4.87$$; hydrogen chloride, $$pK_a=8.55$$.
Also given is an autodissociation constant, whose base-10 logarithm is $$-14.45$$. Thus whereas we render $$pK_a+pK_b=14$$ in water under ambient conditions, the corresponding constant in glacial acetic acid would be $$14.45$$. As an example, citing the hydrogen chloride acid dissociation constant given above, we can compute the $$pK_b$$ of the conjugate base chloride ion as $$14.45-8.55=5.90$$ (significant zero).
• From the autodissociation constant aso given in the abstract, we calculate that the neutral "pH" in acetic acid is about 7.2. Perchloric acid with $pK_a$ between two and three units less can reach that condition with most bases; hydrogen chloride can't (unless you go far beyond the equivalence point) and sulfuric acid is marginal at best. Commented Oct 12, 2023 at 12:16