Can a weak acid solution ever be alkaline?

[Allison Peng 1D]

Let's say there's an acid (HA) with a Ka value that is super small (like 10^-12) and there is a solution of HA in water with a low concentration. In this case, could it be basic?

Since if the Ka value for HA is very small, that means that the Kb value for A- should be very large (in this case, like 10^-2). If A- is a stronger base, wouldn't it produce OH- ions in water and make it basic?

Side note: can A- actually take place in two reactions?
A- + H3O+ <--> HA + H2O (the reverse reaction from dissociation of HA, which must be occurring since an equilibrium reaction goes in both ways)
A- + H2O <--> HA + OH- (protonation of A-, and A- acting as a base).
In a solution of HA, do both of these reactions happen?

The reasoning I can think of of why this cannot happen is because in order for the hydroxide produced by A- to substantially impact pH, there has to be a high enough concentration of it, which will not happen since barely any HA will dissociate and there will barely be any A- in the solution at all. Is there another explanation for this?

[Aditya Desai 1A]

No, because there is no A- present in solution - only HA. Any A- formed by the negligible, minute dissociation of our weak acid will form both A- *and* H3O+, which will react with the A- (instead of H2O) creating no OH- but only more H2O.

Same logic for other question. Technically, yes, you can have both happening, but H3O+ is so much more acidic than H2O that the H2O deprotonation basically doesn't happen when H3O+ can be deprotonated.

[Allison Peng 1D]

Super helpful double checking my train of thought, thanks!

[Aditya Desai 1A]

No, because there is no A- present in solution - only HA. Any A- formed by the negligible, minute dissociation of our weak acid will form both A- *and* H3O+, which will react with the A- (instead of H2O) creating no OH- but only more H2O.

Same logic for other question. Technically, yes, you can have both happening, but H3O+ is so much more acidic than H2O that the H2O deprotonation basically doesn't happen when H3O+ can be deprotonated.

[605733348]

I think no.