Explain the effect of adding a catalyst on rate of reaction.
The Correct Answer and Explanation is:
A catalyst increases the rate of a chemical reaction without being consumed in the process. It does this by providing an alternative reaction pathway with a lower activation energy. Activation energy is the minimum energy required for reactants to collide and form products. By lowering this energy barrier, a catalyst allows more reactant molecules to have enough energy to react, even at lower temperatures. This leads to an increase in the number of successful collisions per unit of time, thus speeding up the reaction.
There are two types of catalysts: homogeneous and heterogeneous. A homogeneous catalyst is in the same phase (state) as the reactants, typically a liquid or gas. For example, in a reaction between gaseous reactants, a gaseous catalyst can lower the activation energy. On the other hand, a heterogeneous catalyst is in a different phase, such as a solid catalyst used in liquid or gas-phase reactions. An example is the catalytic converter in cars, which uses a solid catalyst to speed up reactions that convert harmful gases into less harmful substances.
Importantly, a catalyst does not affect the equilibrium position of a reversible reaction. It only increases the rate at which equilibrium is reached, not the concentration of the products or reactants at equilibrium. After the reaction, the catalyst remains unchanged and can be used again. However, catalysts are not 100% efficient and can become deactivated over time due to factors like contamination or extreme conditions.
In summary, the primary effect of adding a catalyst to a reaction is to increase its rate by lowering the activation energy, which allows the reaction to proceed more quickly under the same conditions.
