Which of the following best describes the result of using a catalyst in a chemical reaction?
A.
The reaction is completed in a shorter amount of time.
B.
The yield of product is increased.
C.
A greater amount of heat energy is released by the reaction.
D.
A more desirable product is often formed.
The correct answer and Explanation is :
The correct answer is:
A. The reaction is completed in a shorter amount of time.
Explanation:
A catalyst is a substance that accelerates the rate of a chemical reaction without itself being consumed or permanently altered in the process. The primary role of a catalyst is to provide an alternative reaction pathway with a lower activation energy. Activation energy is the minimum energy required for a reaction to occur.
When a catalyst is added to a reaction, it increases the rate at which reactants are converted into products. This is achieved because the catalyst lowers the activation energy barrier, making it easier for the reactants to form products. As a result, the reaction reaches equilibrium faster compared to a reaction without the catalyst. However, it is important to note that while a catalyst speeds up the reaction, it does not change the equilibrium position or the yield of the product. The final amount of product and the position of equilibrium remain the same; only the time it takes to reach that equilibrium is reduced.
The other options listed are not correct in describing the effect of a catalyst:
- B. The yield of product is increased: A catalyst does not affect the equilibrium position of a reaction, so it does not change the yield of the product. It only affects the rate at which equilibrium is reached.
- C. A greater amount of heat energy is released by the reaction: A catalyst does not influence the total energy change of the reaction. The amount of heat energy released or absorbed is determined by the reaction itself, not by the presence of a catalyst.
- D. A more desirable product is often formed: The catalyst does not alter the nature of the products. It only affects how quickly the reaction proceeds to form the same products that would be formed without it.
In summary, the main effect of a catalyst is to decrease the time required for a reaction to complete by providing a more efficient pathway for the reaction to occur.