Answer: PO 4 3-.
- A PO<sub>4</sub><sup>3-</sup>
- B Cl<sup>-</sup>
- C SO<sub>4</sub><sup>2-</sup>
- D Na<sup>+</sup>
Correct answer: A. PO<sub>4</sub><sup>3-</sup>
Explanation: By the Hardy-Schulze rule a positive sol is coagulated by the oppositely charged ion of highest charge, i.e. PO<sub>4</sub><sup>3-</sup>.
A typical adsorption isotherm: x/m (mass adsorbed per gram of adsorbent) rises steeply at low pressure, then flattens into a saturation plateau as the adsorbent surface fills up.
Concept context
Explore the chemistry that happens at interfaces, from catalysts that speed up industrial reactions to colloids like milk, smoke, and gels that surround us every day.