Strong bases: Hydroxide ions

Strong bases are those compounds that totally dissociate in water, yielding some cation and the hydroxide ion. It is the hydroxide ion that we normally refer to as the base, because it is what accepts the proton. Calculating the hydroxide ion concentration is really straightforward. Suppose that you have a 1.5 M (1.5 mol/L) NaOH solution. The sodium hydroxide, a salt, completely dissociates (breaks apart) into ions:

NaOH → Na⁺ + OH^–

If you start with 1.5 mol/L NaOH, then you have the same concentration of ions:

[Na⁺] = 1.5 and [OH^–] = 1.5