How Bromoalkanes are prepared?

Explanation

Working : Sodium is extracted by the electrolysis of fused sodium chloride. This process is known as Down.s process. In this process the electrolysis is done with a fused mixture of sodium chloride (40%), calcium chloride (60%) and traces of potassium fluoride. calcium chloride and potassium fluoride are used to decrease the melting point of sodium chloride from 1085 to 873 K temperature.

Down.s cell consists of a steel tank. a circular graphite anode is surrounded by a hood shaped iron cathode. these two electrodes are separated by wire gauze so that sodium and chlorine do not come in contact with each other.
Reactions: The chemical reactions take place during electrolysis as `Na hArr underset(("Molten"))(Na^(+)+Cl^(-))`
At cathode: `Na^(+)+e^(-) to Na" At anode:"underset(Cl+Cl to Cl_(2))(Cl^(-) to Cl+e^(-))`
Sodium metal is liberated at the cathode and chlorine gas is liberated at the anode.