Question

$pH$ of a $0.001$M $NaOH$ solution will be:

• A. $9$
• B. $3$
• C. $11$
• D. $12$

Answer 1

The correct option is C $11$

$\left[O{H}^{-}\right]={10}^{-3}$

$\Rightarrow pOH=-\log \left[O{H}^{-}\right]=-\log \left[{10}^{-3}\right]=3$

$pH+pOH=14$

$\Rightarrow pH+3=14$

$\Rightarrow pH=11$

$\therefore pH$ of ${10}^{-3}M$ $NaOH=11$