Question

Calculate the pH of $\frac{N}{1000}$ sodium hydroxide $\left(NaOH\right)$ solution assuming complete ionization.

Answer 1

For monoacidic base $NaOH$, molarity $=$ normality

$\left[O{H}^{-}\right]=\left[NaOH\right]=\frac{N}{1000}=0.001N=0.001M$

$pOH=-lo{g}_{10}\left[O{H}^{-}\right]$
$pOH=-lo{g}_{10}0.001$
$pOH=3$
$pH=14-pOH$
$pH=14-3$
$pH=11$