Assuming that \( \mathrm{Ba}(\mathrm{OH})_{2} \) is completely ionised in aqueous solution under the given conditions, t…

Assuming that \( \mathrm{Ba}(\mathrm{OH})_{2} \) is completely ionised in aqueous solution under the given conditions, the concentration of \( \mathrm{H}_{3} \mathrm{O}^{+} \)ions in \( 0.005 \mathrm{~M} \) aqueous solution of \( \mathrm{Ba}(\mathrm{OH})_{2} \) at 298 \( \mathrm{K} \) is \( \mathrm{x} \times 10^{-12} \mathrm{~mol} \mathrm{~L}^{-1} \). Find the value of \( \mathrm{x} \).

[JEE Main 2021, 25 Jul (Shift 2)]