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 ** Electrolysing Brine- 6.3 **

Brine is sodium chloride solution.

When it is __electrolysed__ (an electric current passed through it) we get these 3 products: See the diagram below for how this works.



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We can use the chemicals created by electrolysing salt in many ways...

Chlorine:
 * Used in water and sewage treatment.
 * Used in the manufacture of PVC, textiles, solvents, titanium dioxide, pesticides, drugs to treat heart disease, leukaemia and arthritis.

Bleach:


 * Used for treating water for swimming pools.
 * Used for household bleach.

Hydrochloric acid:


 * Used for cleaning materials.
 * Used for water and effluent treatment.
 * Used in the manufacture of medicines, food products (e.g. soy sauce, gelatin) cosmetics, synthetic rubber, precious metals (e.g. gold.)

Hydrogen:


 * Used in the manufacture of margarine.

Sodium Hydroxide:


 * Used for purifying petroleum and natural gas.
 * Used for degreasing metals.
 * Used in water and sewage treatment,.
 * Used in the manufacture of paper, cellulose wrapping, soaping and detergents, aluminium and titinium dioxide.

Purifying Copper- 6.4 **

A bar of impure copper is used as the anode (+) and a thin sheet of pure copper is the cathode (-). The electrolysis takes place in a solution containing copper ions (usually copper sulphate solution).  At the positive electrode copper atoms are OXIDISED. They form copper ions and go into the solution:
 * When removed from its ore, copper can be 99% pure. However, in order to acheive maximum conductivity, these impurities must be removed. Here is how; ELECTROLYSIS!!

Cu (s) > Cu(2+) (aq) + 2 e-

At the negative electrode copper ions are reduced. They form copper atoms which are deposited on the electrode:

Cu(2+) (aq) + 2 e- > Cu (s) media type="custom" key="3596706"