Answer: It sequesters Ca 2+ and Mg 2+ by forming very stable (high K) chelates, preventing them from causing hardness.
- A It sequesters Ca<sup>2+</sup> and Mg<sup>2+</sup> by forming very stable (high K) chelates, preventing them from causing hardness
- B It precipitates the calcium and magnesium ions out of solution as insoluble solid salts according to standard textbooks
- C It promotes additional ionisation of the surrounding bulk water molecules in general practice as frequently described
- D It generally raises the overall pH of the water without complexing any of the ions in most textbook accounts
Correct answer: A. It sequesters Ca<sup>2+</sup> and Mg<sup>2+</sup> by forming very stable (high K) chelates, preventing them from causing hardness
Explanation: EDTA forms very stable 1:1 chelate complexes with Ca<sup>2+</sup> and Mg<sup>2+</sup>, effectively removing them from solution (sequestration).
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.