Question

The concentration of $H_3{O}^{+}$ ions in pure water is ${10}^{-6}mol{dm}^{-3}$. The corresponding concentration of ${OH}^{-}$ ions will be:

• A. ${10}^{-14}mol{dm}^{-3}$
• B. ${10}^{-8}mol{dm}^{-3}$
• C. ${10}^{-6}mol{dm}^{-3}$
• D. ${10}^{-7}mol{dm}^{-3}$

Answer 1

Answer: (C)

${10}^{-6}mol{dm}^{-3}$

In pure water concentration of $H^{+}$ ions are always equal to $O{H}^{-}$.

Concentration of $H_3{O}^{+}$ is the concentration of $H^{+}$.

So $\left[O{H}^{-}\right]=\left[H^{+}\right]={10}^{-6}mold{m}^{-}3$

Hence, option $C$ is correct.