Which type of water hardness is caused by calcium carbonate and magnesium bicarbonate and can be removed by boiling then filtering?

Which type of water hardness is caused by calcium carbonate and magnesium bicarbonate and can be removed by boiling then filtering?

• A. Temporary Hard Water
• B. Permanent Hard Water
• C. Soft Water
• D. Salt Water

Answer: (A)

Temporary hardness is caused by dissolved bicarbonate salts of calcium and magnesium (Ca(HCO3)2 and Mg(HCO3)2). When such water is boiled, the bicarbonates decompose to carbonate, releasing CO2, and calcium and magnesium carbonates precipitate out as solid carbonates. These can then be removed by filtering, so the water becomes softer. Permanent hardness, from sulfates or chlorides of these ions, doesn’t disappear with boiling. So the described water is temporary hard water.

Temporary hardness is caused by dissolved bicarbonate salts of calcium and magnesium (Ca(HCO3)2 and Mg(HCO3)2). When such water is boiled, the bicarbonates decompose to carbonate, releasing CO2, and calcium and magnesium carbonates precipitate out as solid carbonates. These can then be removed by filtering, so the water becomes softer. Permanent hardness, from sulfates or chlorides of these ions, doesn’t disappear with boiling. So the described water is temporary hard water.