Pooja lived in an area where the water, which was obtained from a tube-well, was usually hard. One day, there was a water shortage and she took boiled water from the kettle to wash her face. To her surprise the soap lathered well in that water. Why did this happen?

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Solution

This happened because Pooja used soft water instead of hard water. The hardness of water was removed by boiling. The hardness in water is caused by bicarbonates and sulphates of calcium and magnesium. When water is boiled, soluble bicarbonates decompose into insoluble carbonates, which can be removed by filtering water through a fine cloth. This converts hard water into soft water.

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