Chapter 13, Problem 101E

A 0.010 M solution of the weak acid HA has an osmotic pressure (see chapter on solutions and colloids) of 0.293 atm at 25 °C. A 0.010 M solution of the weak acid HB has an osmotic pressure of 0.345 atm under the same conditions.

(a) Which acid has the larger equilibrium constant for ionization

$\text{HA}\left[\text{HA}\left(aq\right)\rightleftharpoons {\text{A}}^{-}\left(aq\right)+{\text{H}}^{+}\left(aq\right)\right]$ or $\text{HB}\left[\text{HB}\left(aq\right)\rightleftharpoons {\text{H}}^{+}\left(aq\right)+{\text{B}}^{-}\left(aq\right)\right]$?

(b) What are the equilibrium constants for the ionization of these acids?

(Hint: Remember that each solution contains three dissolved species: the weak acid (HA or HB). the conjugate base (A- or B- and the hydrogen ion (H⁺). Remember that osmotic pressure (like all colligative properties) is related to the total number of solute particles. Specifically for osmotic pressure, those concentrations are described by molarities.)