Question

What would a 0.12M solution of an acid that ionizes only slightly in solution be termed?

Answer 1

Regardless of its concentration, it is called a weak electrolyte. Weak electrolytes dissociate slightly in solution, i.e. they form few ions in solution for a given sample of solute.

(We thus expect the conductivity of this solution to be low.)

Since it is an acid, it is also a weak acid.

We thus describe this small dissociation, or ionization, using the acid dissociation constant,

`K_a = (["A"^(-)]["H"^(+)])/(["HA"])`

for the reaction

`"HA"(aq) rightleftharpoons "A"^(-)(aq) + "H"^(+)(aq)`,

and for weak acids, `K_a` tends to be smaller than `1`. For example, acetic acid has `K_a = 1.76 xx 10^(-5)`.