Question

State Faraday’s second law of electrolysis.

Answer 1

Hint : Hint : Faraday’s Law of electrolysis is given by Michael Faraday in $1834$. Qualitative laws in chemistry are used to determine or express magnitudes of electrolytic effects. Faraday's laws are used in the determination of chemical changes. The most important use of this law is used to detect the amount of substance deposit at electrodes.

Complete step by step solution:
Faraday’s second law of electrolysis states that ‘’The masses of different ions liberated at the electrodes, when the same amount of electricity is passed through different electrolytes are directly proportional to their chemical equivalents”. Thus it can be said that the electro-chemical equivalent which is represented by $Z$ of an element is directly proportional to their equivalent weight $(E)$.
Let ${W_1},{W_2}$ are the deposited amount of any substance and ${E_1},{E_2}$ are their respective equivalent weights then according to second law,
$ \Rightarrow \dfrac{{{W_1}}}{{{W_2}}} = \dfrac{{{E_1}}}{{{E_2}}}$ $ \Rightarrow Z \propto E$
Thus the above equation can be used in numerical problems.
One Faraday can be defined as the quantity of electricity flowing through an electrolyte that will liberate one gram-equivalent of any substance at any electrode. Faraday’s constant $(F)$ is charged in coulombs $(C)$ of one mole electrons. We can calculate the value of $1$ Faraday by multiplying the charge on one electron which is equal to $1.6 \times {10^{ - 19}}$ by Avogadro’s number $(6.022 \times {10^{ - 19}})$ .

Hence the value of Faraday’s constant is equal to $96485Cmo{l^{ - 1}}$.

Additional information – Equivalent weight is also called gram equivalent. One gram equivalent mass can combine or displace indirectly or directly with$1.008$ parts by mass of hydrogen or $8$ parts by mass of oxygen or $35.5$ of chlorine.

Note : Faraday’s second law is very useful for the determination of chemical equivalents of different electrolytes. The current of $96500$ coulombs are called on Faraday charge after the name of the scientist. Thus Faraday is defined as the quantity of charge which deposits or liberates one gram equivalent of a substance.