Answer: Greater subdivision increases the total surface area available for adsorption of reactant molecules.
- A Finely divided catalysts undergo a change in chemical composition compared with the bulk form
- B Finely divided catalysts react chemically with the reactants rather than acting catalytically
- C Greater subdivision increases the total surface area available for adsorption of reactant molecules
- D Bulk catalysts generally have a higher melting point, which tends to slow down the reaction
Correct answer: C. Greater subdivision increases the total surface area available for adsorption of reactant molecules
Explanation: Catalytic activity in heterogeneous catalysis depends on the surface area available for adsorption of reactants; finely dividing the catalyst greatly increases this surface area, raising activity.
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.