Question

$NaOH$ can also be prepared by electrolysis of aqueous $NaCl$. Amount of $NaOH$ formed when $0.445L$ of $NaCl$ (aq) is electrolysed for $137$ s with a current of $1.08A$ is $0.06$g. The pH of this solution is :

• A. $11.70$
• B. $11.53$
• C. $11.83$
• D. data is incomplete

Answer 1

The correct option is B $11.53$

Mass produced of $NaOH=0.06g$.,

Volume of solution $=0.445L$

$0.06gNaOH$ is present in $0.0445L$.

Conc. in mol $L^{-1}=\frac{0.06}{40\times 0.0445}$ $=3.37\times {10}^{-3}M$

$\therefore$ $\left[O{H}^{-}\right]=3.37\times {10}^{-3}M$

$pOH=2.47$

$pH=14-2.47=11.53$