Application of Electrolysis: Electro Refining
* Electro refining is defined as the process by which an impure metal is purified electrolytically to obtain a pure metal.
* In this method, the impure metal is cast into the anode and a strip of the same metal in its pure form is used as the cathode.
* An aqueous solution containing a soluble salt of the same metal is used as the electrolyte.
* During electro refining, pure metal is deposited on the cathode.
* The more basic impurities dissolve in the electrolyte solution, while the insoluble impurities, particularly the less basic ones, settle at the bottom of the electrolyte as anode mud.
Acids, Bases and Salts as Electrolytes
* Strong electrolytes completely dissociate in their molten aqueous states, so they are good conductors of electricity.
* Weak electrolytes partially dissociate in their molten or aqueous states, so they are poor conductor of electricity.
* Strong acids such as hydrochloric acid, sulphuric acid and nitric acid are strong electrolytes.
* Weak acids such as acetic acid, formic acid and carbonic acid are weak electrolytes.
* Strong bases like sodium hydroxide, potassium hydroxide and lithium hydroxide act as strong electrolytes.
* Weak bases like ammonium hydroxide, calcium hydroxide and magnesium hydroxide are weak electrolytes.
* Salts like lead bromide, silver nitrate and copper chloride act as strong electrolytes.
* Salts like sodium carbonate, potassium bicarbonate and lead acetate are weak electrolytes.
