Uses of Salts

The following are some of the ways salts can be used:

1. As fertilizers, e.g. NPK fertilizers - contain NH₄NO₃, (NH₄)₂SO₄, (NH₄)₃PO₄ and KCl - these salts provide a source of N₂, P and K to the soil.

2. As fungicide - e.g. CuSO₄ - CuSO₄ solution can be used to kill the fungus that causes potato blight by spraying on the potato plants.

3. As baking soda - NaHCO₃, (baking soda) is added to self - raising flour. When heated, it decomposes, and the carbon (IV) oxide which is produced causes the dough to rise.

4. For making plaster - plaster of paris is made by heating CaSO₄ and water

CaSO₄ + 2H₂O → CaSO₄. 2H₂O

When plaster of paris is mixed with water, it combines and sets to form a strong plaster.

5. As "barium meal” - patients who are suspected of having a stomach ulcer may be given a “barium meal”. It contains BaSO₄. After a barium meal, an x-ray photograph of the body shows the path taken by the salt.

6. In photography - silver bromide, AgBr, is the salt which is used in the black and white photography. A photographic film is a piece of celluloid covered with a thin layer of gelatin containing silver bromide.

Methods of Preparation of Salts