Determine the hydronium and hydroxide ion concentrations in a solution

Question

Determine the hydronium and hydroxide ion concentrations in a solution that is 2.0 × 10-2 M NaOH.

Answer 1

When you mix this in water you will get

 

NaOH ---->  Na⁺   + OH^-

 

This is a strong base.  When this dissociates the original concentration of the NaOH is the same as the concentration of the OH^-.  You then know that [H+][OH-=1x10^-14.  Since we said that 2.0 x 10^-2 is the OH concentration you would plug it into the equation and solve for the H+ concentration.