Question

How to remove the hardness of water temporarily?

Answer 1

Hard Water

• In hard water, the mineral content is high.
• In hard water, the content of Calcium (Ca) and Magnesium (Mg) is high.
• In hard water, the salts of Calcium and Magnesium are found as carbonates, sulfates, and chlorides.

Removing the Hardness of Water

• The hardness of water can be removed temporarily by adding Calcium hydroxide ($\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$).
• Calcium hydroxide acts on the bicarbonate salts of hard water and converts them to insoluble carbonates.
• The insoluble carbonates formed can be easily removed from water by using filtration techniques.
• This leads to water softening.

Hence, to remove the hardness of water temporarily Calcium hydroxide is added to the water.