Answer: gelatin is the better protective colloid.
- A starch is the better protective colloid
- B gelatin is the better protective colloid
- C both protect the sol equally well
- D neither can protect the gold sol
Correct answer: B. gelatin is the better protective colloid
Explanation: A smaller gold number means better protection, so gelatin (0.005) is far more effective than starch (25).
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.