Question

The number of faradays of electricity required to decompose $100$ ml water (density $=0.99$ gm/ml) is:

• A. $2$
• B. $11$
• C. $100$
• D. $5.5$

Answer 1

Answer: (B)

$11$

$100$ ml water density $=0.99g/ml$

$\therefore massof{H}_{2}O=0.99\times 100=99g$

$molesof{H}_{2}O=\frac{99}{18}=\frac{11}{2}$

$H_{2}O\to 2H_2+O_2$

$2H^{+}+2e^{-}\to H_2$

$1$ mole $H_{2}O$ requires $2$ moles of $e^{-}$

$Totalcharge=1F\times no.of{e}^{-}requires$

$=2\times \frac{11}{2}$

$=11F$