Question

Calculate the time required to liberate $56c{m}^3$ of hydrogen at $STP$, if $5$ amperes of current flows.

Answer 1

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

mol. of $H_2$ liberated $=\frac{56{cm}^3}{22400{cm}^3}\left(\frac{givenvol.}{vol.ofSTPof1mole}\right)$

$=2.5\times {10}^{-3}mol$

mol of Faraday $=2\times 2.5\times {10}^{-3}mol$ as ${2e}^{-}$ are required.

mol. of Faraday $=\frac{Q}{F}=\frac{I\times t}{96500}$

$2\times 2.5\times {10}^{-3}=\frac{5\times t}{96500}$

$t=482.52seconds$