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Hydrogen — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryHydrogen3 Marks
Question
What causes the temporary and permanent hardness of water?
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Answer

Temporary hardness of water is due to the presence of bicarbonates of calcium and magnesium in water i.e., $\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2$ and $\mathrm{Mg}\left(\mathrm{HCO}_3\right)$ in water. Permanent hardness of water is due to the presence of soluble chlorides and sulphates of calcium and magnesium i.e., $\mathrm{CaCl}_2, \mathrm{CaSO}_4, \mathrm{MgCl}_2$ and $\mathrm{MgSO}_4$.

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