State and explain Faraday's law of electrolysis.

Faraday's Law of electrolysis are:

Faraday's first law:

The amount of chemical reaction which occurs at any electrode during electrolysis is proportional to the quantity of electricity passed through it.

       Is w gram of substance is produced on passing through amount of electricity for the electrolyte, then

                        W∞Q

or                    W=ZQ

                        

                        Here Z is a constant and is called electrochemical equivalent.

(b) Faraday's second law:

The amount of different substances liberated by the same quantity of electricity passing through the electrolytic solutions are proportional to their chemical equivalent weights.

       Consider three voltmeters containing solutions of copper sulphate; silver nitrate in acidulated water. Let this voltmeters are connected in series and the same amount of current is passed through them for a given time. If Q is the change passed through these electrolytes, then according to Faraday's first law of electrolysis.

       

                W   =Z       Q (i)

                   Ag    Ag

                W    =Z       Q (ii)

                   Cu     Cu

               W   =Z      Q (iii)

                  H     H

               Taking the ratio of (i),(ii),(iii)

W   =Z     =>W   =Z   ×96500=E

  Ag   Ag.       Ag.   Ag               Ag

W  =Z    =>W  =Z   ×96500=E

  Cu   Cu      Cu   Cu                Cu

W =Z  =>W =Z ×96500=E

  H    H      H    H              H

Where, w=mass of substance deposited or liberated

Z= electrochemical equivalent of substance

QE= equivalent mass of substances.