If excess of Ca(OH)2 is added to hard water in clark’s method.
The correct option is B Temporary hardness is not removed
Clark’s method to remove the hardness of water
In Clark’s water softening method, hard water is treated with Ca(OH)2 (slaked lime). Calcium hydroxide is Clark’s reagent. It removes the hardness of water by converting bicarbonates into carbonate. Water softening by Clarke’s process uses calcium hydroxide (lime). It removes temporary hardness.
Reaction
Ca(HCO3)2+Ca(OH)2⟶2CaCO3+2H2O
This method involves the addition of slaked lime to water either in solid or in liquid form. This results in the conversion of soluble bicarbonates to insoluble carbonates.
If an excess of Ca(OH)2 is added, Temporary hardness is not removed due to the formation of calcium bicarbonate.
2CaCO3+Ca(OH)2⟶2Ca(HCO3)2+2H2O