Sodium is found in many compounds. Its main ore is rock salt which contains
sodium chloride and potassium chloride. Sodium is extracted from sodium
chloride by electrolysis. It is the sixth most abundant element. 
When burned in air, sodium produces an orange flame. Sodium reacts violently
with water. 


Sodium chloride - also known as common salt or table salt. Occurs naturally
in rock salt and sea water. Its uses include flavouring and preserving food.

Sodium hydrogencarbonate - also known as sodium bicarbonate or bicarbonate
of soda. This gives off carbon dioxide when heated, so is used in baking to
make dough rise. It is also used in anti-indigestion tablets.