SSC JE Civil Engineering 23-Sep-2019 Shift 1 Solved Paper

Temporary hardness of water is due to the presence of calcium hydrogencarbonate Ca $(\mathit{H}\mathit{C}\mathit{O}{}_3^{}{)}_{2\left(\mathit{a}\mathit{q}\right)}^{}$ and magnesium hydrogencarbonate Mg(HCO${}_3^{}{)}_{2\left(\mathit{a}\mathit{q}\right)}^{}$. Both calcium hydrogencarbonate and magnesium hydrogencarbonate decompose when heated. The original insoluble carbonates is reformed. This happens when water is boiled.