Question

Statement 1: A solution with a $pH$ of $12$ has a higher concentration of hydroxide ions than one with a $pH$ of $10$.
Statement 2: $\left[H^{+}\right]\left[O{H}^{-}\right]$ must equal ${10}^{-14}$.

• A. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.
• B. Both the Statement 1 and Statement 2 are correct, but Statement 2 is not the correct explanation of Statement 1.
• C. Statement 1 is correct, but Statement 2 is not correct.
• D. Statement 1 is not correct, but Statement 2 is correct.

Answer 1

The correct option is B Both the Statement 1 and Statement 2 are correct, but Statement 2 is not the correct explanation of Statement 1.

For a solution with $pH=12$, $pOH$ is equal to $2[\because pH+pOH=14]$

Hence, $\left[O{H}^{-}\right]={10}^{-2}$

For a solution with $pH=10$, $pOH$ is equal to $4$

$\therefore \left[O{H}^{-}\right]={10}^{-4}$

$\because {10}^{-4}<{10}^{-2}$

The hydroxide ion concentration is higher for a solution with $pH=12$ then one with a $pH$ of $10$.

Statement $2\left[H^{+}\right]\left[O{H}^{-}\right]={10}^{-14}$

is true as it is the ionic product of water. But it's not the correct explanation of statement $1$