Answer: Forming soluble complexes with Ca2+ and Mg2+ ions (sequestration).
- A Forming soluble complexes with Ca2+ and Mg2+ ions (sequestration)
- B Precipitating the calcium and magnesium ions as insoluble salts
- C Exchanging the hardness ions for sodium ions on a resin bed
- D Removing the hardness ions through simple distillation
Correct answer: A. Forming soluble complexes with Ca2+ and Mg2+ ions (sequestration)
Explanation: Calgon sequestrates Ca2+ and Mg2+ by forming stable soluble complexes, preventing them from causing hardness.
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.