Question

Give balanced equation to show how temporary hardness enters into water.

Answer 1

Temporary hardness: Enters in water when rain water containing CO₂ falls on earth and combines with limestone [CaCO₃] & magnesite [MgCO₃] layers forming respective soluble bicarbonates.

\[\ce{CaCO3 + H2O + CO2 -> \underset{\text{Cal. bicarbonate}}{Ca[HCO3]2}}\]

\[\ce{MgCO3 + H2O + CO2 ->\underset{\text{Magnesium bicarbonate}}{Mg[HCO3]2}}\]