Question

During the electrolysis of water 4 mol of electrons were transferred from anode to cathode. Calculate the total volume of gases produced at STP.

Answer 1

Anode : $2H_{2}O\left(l\right)\to O_2\left(g\right)+4H^{+}\left(aq\right)+4e^{-}$

Cathode : $2H^{+}\left(aq\right)+2e^{-}\to H_2\left(g\right)$

From the half equation, $4$ moles of electrons will give $1$ mole of $O_2$ and $2$ moles of $H_2$

Total number of moles of gases$=1+2=3$ moles

Molar gas volume at STP$=22.4$ litres

Total volume of gases$=3\times 22.4=67.2$ litres.