Temporary hardness in water is also known as:

Concept

Water hardness is caused mainly by dissolved calcium and magnesium ions. When hardness is associated with bicarbonate alkalinity, heating forms sparingly soluble carbonate precipitates and removes much of it; hardness from sulphates, chlorides, or nitrates persists on boiling.

Application

The qualifier temporary signals hardness that can be reduced by boiling. Among the given names, carbonate hardness is the bicarbonate-derived form.

Contrast and cross-check

• Sulphate hardness is produced by dissolved calcium or magnesium sulphates and belongs to non-carbonate hardness.

• Nitrate hardness is produced by dissolved calcium or magnesium nitrates and belongs to non-carbonate hardness.

• Chloride hardness is produced by dissolved calcium or magnesium chlorides and belongs to non-carbonate hardness.

• Carbonate hardness is produced by dissolved calcium or magnesium bicarbonates; boiling converts them into sparingly soluble carbonate precipitates.

Therefore, temporary hardness is also called carbonate hardness.