1. Applications of neutralization

2. Adjusting soil pH The soil is too acidic：
Liming of soil [ to neutralize the acid in soil ]
Add powdered limestone < a natural form of CaCO3 >
Add quicklime < CaO >
Add slaked lime < Ca(OH)2 >
The soil is too alkaline：
Add ammonium sulphate < (NH4)2SO4 >
( which is acidic when dissolved in water )

3. Neutralizing excess acid in stomach
Gastric juice [to help digest food] is acidic as it contains mainly hydrochloric acid.
If our stomach secrets an excess of this acid , we may suffer from indigestion.
We can treat indigestion by taking antacids.
( Drugs which contain weak base such as Mg(OH)2 and Al(OH)3 )
[To neutralize the excess acid in the stomach]

4. Treating industrial liquid waste
Liquid waste from industries (e.g. electroplating and dyeing )are often acidic.
If acidic liquid waste were allowed to run directly into rivers ,it would cause water pollution and kill water life.
Treated with Ca(OH)2or Na2CO3 before discharge (排放) .
[to neutralize the acid in liquid waste & to reduce pollution]
Alkaline liquid waste is often treated with H2SO4 before discharge .
[to neutralize the alkaline substances in liquid waste]

5. Producing fertilizer
Many common fertilizers are produced by neutralization .
e.g. HNO3 + NH3 → NH4NO3
[After crystallization , NH4NO3 crystals are packed and sold to the farmers . ]

6. THE END