11. pH of Mixtures of Acids and/or Bases

• Mixture of Two Strong Acids (Bases)

Both acids are completely ionized. So they both contribute independently to the H⁺-concentration in the solution.
Both bases are completely dissociated. So they both contribute independently to the OH^--concentration in the solution.

• Mixture of a Strong Acid (Base) and a Weak Acid (Base)

The strong acid is completely ionized. On the other hand, the weak acid will donate only a few protons and can be neglected.
The strong base is completely dissociated. On the other hand, the weak base will accept only a few protons and thus will produce only a few OH^--ions. It can be neglected.

• Mixture of an Acid and a Base

Mixing an acid and a base always will result in a reaction in which a salt will be formed. The stoichiometric result of that reaction will determine the method of calculating the pH.

Summary

pH of mixtures of acids and or bases

The way of calculation pH will depend on the strength of the acid/base.