Question

Explain the factors affecting the rate of chemical reaction with example.

Answer 1

The factors that affect the rate of a chemical reaction are as follows:

1. Nature of the reactants: Nature or reactivity of reactants influences the rate of a chemical reaction.
   E.g. Al is more reactive than Zn. Therefore, the rate of reaction of Al with hydrochloric acid is higher than that of Zn.
2. Size of the particles of the reactants: Smaller the size of the reactant particles, higher is the rate of the reaction.
   E.g. When HCl is added to pieces of Shahabad tile, the CO₂ effervescence is formed slowly. However, when HCl is added to Shahabad powder, the CO₂ effervescence is formed at a faster rate.
3. Concentration of the reactants: The rate of a chemical reaction increases with increase in the concentration of the reactants.
   E.g. Dilute HCl reacts slowly with calcium carbonate, CaCO₃ whereas concentrated HCl reacts rapidly with CaCO₃.
4. Temperature of the reaction: Higher the temperature, faster is the rate of a chemical reaction.
   E.g. The temperature in the refrigerator is low. So, the rate of decomposition of perishable foodstuffs is low and it remains fresh for a longer time.
5. Catalyst: Presence of catalyst increases the rate of a chemical reaction.
   E.g. The decomposition of hydrogen peroxide into water and oxygen takes place slowly at room temperature. However, the same reaction occurs at a faster rate on adding manganese dioxide (MnO₂) powder in it.