Question

State the first and second law of electrolysis.

Answer 1

First law of electrolysis : The mass of any substance deposited or liberated at any electrode is directly proportional to the quantity of electricity passes. Thus if $w_g$ of the substance is deposited on passing $Q$ coulombs of electricity, then $W\propto Q$ or $W=ZQ$ where $Z$ is a constant of proportionally called electrochemical equivalent of the substance deposited. If a current of $C$ amperes is passed for $t$ seconds then
$Q=C\times t$
so at $W=Z\times C\times t$ or,
$W=\frac{\text{Equivalent wt. of the substance}}{96500}\times C\times t$
Second law of electrolysis : When the same quantity of electricity is passed through solutions of different electrolytes connected in the series, the weight of the substance produced at the electrodes is directly proportional to their equivalent weights.
For example, for $CuS{O}_4$ solution and $AgN{O}_3$ connected in the series if the same quantity of electricity is passed then,
$\frac{\text{Weight of Cu deposited}}{\text{Weight of Ag deposited}}=\frac{Eq.wt.ofCu}{Eq.wt.ofAg}$