Potassium hydroxide KOH is a strong base which can completely ionize to form potassium and hydroxide ions.
The equation representing ionization of KOH,
[tex]KOH(aq)-->K^{+}(aq)+OH^{-}(aq)[/tex]
The mole ratio of hydroxide to KOH from the above equation is [tex]\frac{1molOH^{-} }{1molKOH}[/tex]
The given concentration of KOH solution=0.30M
Calculating the concentration of hydroxide ions present in 0.30M KOH solution:
[tex]\frac{0.30mol KOH}{L} *\frac{1mol OH^{-} }{1 mol KOH} =0.30\frac{mol}{L}OH^{-}[/tex]
Therefore the concentration of hydroxide ion will be equal to 0.30 M in a 0.30 M KOH solution.