Question

In water:

• A. temporary hardness is due to the bicarbonates of $C{a}^{2+}$ and $M{g}^{2+}$.
• B. permanent hardness is due to chlorides and sulphates of $C{a}^{2+}$ and $M{g}^{2+}$.
• C. all of the above.
• D. hardness can be removed by adding phosphates.

Answer 1

Answer: (C)

Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate).

Permanent hardness is hardness (mineral content) that cannot be removed by boiling. It is usually caused by the presence of calcium sulfate and/or magnesium sulfates in the water, which do not precipitate out as the temperature increases.