Question

How does the concentration of an acid or base affect the degree of ionization?

Answer 1

Strong acids and bases are those that completely dissociate into ions once placed in solution. For example: NaOH + H₂O → Na⁺ + OH^- So, if we had 2M of NaOH, then we would also have two moles of OH- ions. No matter the concentration of acid or base will always be completely disassociated.

Weak acids and bases, do not behave the same way. This is because the ions do not fully dissociate in the solution. for example:

Calculate the percent dissociation of a weak acid in a 0.050 M HA solution. (K_a = 1.60 x 10^-5)

1) Calculate the [H⁺]:

1.60 x 10^-5 = [(x) (x)] / 0.050

x = [H⁺]= 8.9443 x 10^-4 M

2) Divide the [H⁺] by the concentrationof HA, then multiply by 100:

(8.9443 x 10^-4 M / 0.050 M) x 100 = 1.79% dissociated

We see that if the concentration of HA increase, then the degree of dissociation will decrease