Solutions of Strong Acid or Base - QS Study
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We know that in a solution of a strong acid one can normally ignore the self-ionisation of water as a source of a few extra H+ (aq). The concentration of H+ ions is usually determined just from the strong acid concentration. However, the self-ionisation still exists so there is a small concentration of OH- ions. Similarly, in a solution of a strong base, the self- ionisation still exists and is responsible for a small concentration of H+ ions, while the concentration of OH- ions is usually determined by the strong base concentration.

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Example

Calculate the concentration of H+ ions in 0.010 M NaOH.

NaOH is a strong base then [OH-] = 0.010 M. Substituting [OH-] = 0.010 M into the ion-product expression, we get:

1.0 x 10-14 = (0.010) x [H+]

[H+] = 1.0 x 10-12 M