Answer: Ca(HCO3)2 and Mg(HCO3)2.
- A Ca(HCO3)2 and Mg(HCO3)2
- B CaSO4 and MgSO4 as generally observed
- C CaCl2 and MgCl2 in typical laboratory settings
- D NaCl under usual circumstances
Correct answer: A. Ca(HCO3)2 and Mg(HCO3)2
Explanation: Temporary hardness is caused by bicarbonates of calcium and magnesium, which can be removed by boiling.
Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.
Concept context
The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.