Question

Calculate the H3O
+1 concentration in 0.00500 M NaOH.

Answer 1

first of all lets calculate the concentration of OH^- ions which is $5\times10^{-3}$

and as we know that $[H^+][OH^-]=10^{-14}$

$[H^+]=10^{-14}/(5\times10^{-3})=2\times10^{-12}$