Question

When $1F$ of electricity is passed through acidulated water, $O_2$ evolved is:

• A. $11.2{dm}^3$
• B. $5.6{dm}^3$
• C. $1.0{dm}^3$
• D. $22.4{dm}^3$

Answer 1

Answer: (B)

$5.6{dm}^3$

$2H_{2}O\rightleftharpoons 4H^{+}+2O^{2-}$
$2O^{2-}⟶O_2+4e^{-}$
$4H^{+}+4e^{-}⟶2H_2$
$n=4$
hence, $4F$ charge will liberate
$=1$ mole oxygen $=22.4$ ${dm}^3$ oxygen
$\because$ $1F$ charge will liberate $\frac{22.4}{4}=5.6{dm}^3$ $O_2$