# What happens to hydrogen ions in a base ? and what is the equation ?

Hydrogen ions (or technically, Oxonium ions - ${H}_{3} {O}^{+}$) react with the hydroxide ions ($O {H}^{-}$) in a base to form water.
$O {H}^{-} \left(a q\right) + {H}_{3} {O}^{+} \left(a q\right) \to 2 {H}_{2} O \left(l\right)$
So adding hydrogen ions to a basic solution will cause the $p H$ of the basic solution to decrease as you neutralize the $O {H}^{-}$ ions, which are resonsible for giving a solution high $p H$.