The ions responsible for permanent hardness in water are sulphates of
- Fe\(^{3+}\) and Mg\(^{2+}\)
-
Ca\(^{2+}\) and Mg\(^{2+}\)
- Fe\(^{2+}\) and Fe\(^{3+}\)
- Na\(^{+}\) and Ca\(^{2+}\)
The correct answer is: B
Explanation
Water is considered permanently hard when it contains soluble chlorides and sulphates of calcium and magnesium. These salts do not precipitate out when the temperature increases, so boiling the water will not remove them.
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