Compound responsible for temporary hardness of water is

* Temporary hardness of water is caused by the presence of dissolved soluble bicarbonates of calcium and magnesium (${\text{Ca(HCO}}_3{)}_2$ and ${\text{Mg(HCO}}_3{)}_2$).Permanent hardness is caused by chloride and sulphate salts (${\text{CaCl}}_2$, ${\text{MgSO}}_4$). Dissolved calcium carbonate (${\text{CaCO}}_3$) is highly insoluble.