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Distinguish between temporary and permanent hardness of water. - Leaving Cert Chemistry - Question (b) - 2007
Question (b)
Distinguish between temporary and permanent hardness of water.
Worked Solution & Example Answer:Distinguish between temporary and permanent hardness of water. - Leaving Cert Chemistry - Question (b) - 2007
Step 1
Distinguish between temporary and permanent hardness of water.
Answer
Temporary hardness of water is caused by the presence of dissolved bicarbonate minerals, which can be removed by boiling the water. When the water is boiled, the bicarbonates decompose into insoluble carbonates, which precipitate out, thus softening the water.
On the other hand, permanent hardness is due to the presence of sulfate or chloride compounds of calcium or magnesium. This type of hardness cannot be removed by boiling, as the soluble salts remain in solution regardless of the temperature.