Which of the following methods can be used to remove the temporary hardness of water?
Boiling
Ion exchange
Reverse osmosis
Adding lime
Temporary hardness of water is caused by the presence of bicarbonate ions in the water, which can be removed by boiling the water. When water is boiled, the bicarbonate ions decompose to form carbonate and water, which are not harmful. However, boiling does not remove permanent hardness, which requires other methods such as ion exchange, reverse osmosis, or adding lime.