Question

$I$. The $pH$ of $1M$ $NaOH$ is $13$.
$II$. $pH+pOH=14$.

• A. Statement $I$ is true, Statement $II$ is true and is a correct explanation of the phenomena described in $I$.
• B. Statement $I$ is true, Statement $II$ is false.
• C. Statement $I$ is false, Statement $II$ is true.
• D. Statement $I$ is false, Statement $II$ is false.

Answer 1

Answer: (C)

Statement $I$ is false, Statement $II$ is true.

Since, $NaOH$ is a strong base, we can directly determine the $pOH$ as it is equal to $-\log \left[O{H}^{-}\right]$.

Given that, $\left[O{H}^{-}\right]=1$ $M$

$\therefore pOH=-\log 1=0$

$\because pH+pOH=14$ [From ionic product of water, $\left[H^{+}\right]\times \left[O{H}^{-}\right]={10}^{-14}$]

Hence, Statement $I$ is false, statement $II$ is true.