Question

How is the concentration of hydroxide ions ($O{H}^{-}$) affected when the excess base is dissolved in a solution of sodium hydroxide?

Answer 1

The concentration of $\left(O{H}^{-}\right)$ Hydroxide ions increases when the excessive base is added to the solution of Sodium Hydroxide as the base itself dissociates to give out $O{H}^{-}$ ions which increases their concentration per unit volume.