"III) A constante de dissociação do ácido benzóico 6,5 x 10 -5
Calcule a porcentagem desse ácido que permanece na forma não ionizada, no equilíbrio."
No, nothing about concentration.
This problem is from a chemistry olympiad.
This is a plot I did in Mathematica, probably useless to you, but that helped me see how the answer depends in the concentration.
Blue line is % ionized. Red line is % not ionized. X axis is mol/L concentration.