1. Active centres increases the rate of the reaction by adsorbing and activating the reactants.
2. Increase in the activity of a catalyst by increasing the surface area. Increase in the surface area of metals and metal oxides by reducing the particle size increases the rate of the reaction.
3. The action of catalytic poison occurs when the poison blocks the active centres of the catalyst.
4. A promoter (or) activator increases the number of active centres on the surface.
