Hint : Faraday’s Law of electrolysis, introduced by Michael Faraday in 1834, provides qualitative guidelines in chemistry to measure or express the effects of electrolysis. These laws are essential for determining chemical changes. One of the primary applications of Faraday’s laws is in calculating the quantity of substance deposited at the electrodes.
Complete step by step solution:
Faraday’s second law of electrolysis states that “The masses of different ions released at the electrodes, when the same amount of electricity is passed through various electrolytes, are directly proportional to their chemical equivalents.”
Therefore, it can be concluded that the electrochemical equivalent, denoted as Z, of an element is directly proportional to its equivalent weight (E).
If [latex] W₁ \, [/latex] and [latex] W₂ \, [/latex] represent the amounts of substance deposited, and [latex] E₁ \, [/latex] and [latex] E₂\, [/latex] are their respective equivalent weights, then according to the second law,
[latex] \Rightarrow \frac{W_1}{W_2} = \frac{E_1}{E_2}
\Rightarrow Z \propto E [/latex]
One Faraday is defined as the amount of electricity passing through an electrolyte that will release one gram-equivalent of any substance at an electrode. Faraday’s constant (F) is the charge, in coulombs (C), carried by one mole of electrons. To calculate the value of one Faraday, we multiply the charge on a single electron [latex] 1.6 \times 10^{-19} [/latex] by Avogadro’s number [latex] (6.022 \times 10^{-19}) [/latex]
Therefore, Faraday’s constant is equal to [latex] 96485 \, \text{Cmol}^{-1} [/latex]
Additional information – The equivalent weight, also known as the gram equivalent, is the mass of a substance that can combine with or replace [latex]1.008 \, [/latex] grams of hydrogen, 8 grams of oxygen, or [latex] 35.5 \, [/latex]grams of chlorine.
Note : Faraday’s second law is very useful for the determination of chemical equivalents of different electrolytes. The current of [latex] 96500 \, [/latex]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.