Chemistry

Electrolysis (continued)


Electrolysis Laws

The laws governing electrolysis are the laws that relate the masses of substances produced in the electrodes and the amounts of energy spent on electrolysis.

These laws were established by the English physicist Michael Faradayin 1834.

First Electrolysis Law or Faraday Law

"The mass of the electrolyzed substance in either element is directly proportional to the amount of electrical charge that goes through the solution."

Where:
m = mass of substance
k = proportionality constant
Q = electric charge (Coulomb)

Electrolysis Second Law

"Using the same amount of electrical charge (Q) on several electrolytes, the mass of the electrolyzed substance on either electrode is directly proportional to the gram equivalent of the substance."

m = mass of substance (g)
k2 = proportionality constant
E = gram equivalent

Joining the two laws we have:

We study in physics that:

Where:
Q = electric charge (C)
i = intensity of electric current (A)
t = time (s)

So we have the following expression:

The constant K call of Faraday constant it's equivalent to

Putting all this information together, we have the general electrolysis equation:

The electric charge of 96500 coulomb is called faraday (F).

1 Faraday
- It is the electrical charge that produces one gram equivalent of any element in an electrolysis.
- Approximately 96,500 Coulomb
- Equivalent to the charge of one mol (6,02.1023) of electrons or protons.