Question 34

Increasing the concentration of reactants would increase the rate of an endothermic reaction.

Increasing the concentration of reactants in an endothermic reaction enhances the frequency of collisions between the reactant molecules, thereby raising the reaction rate.

A) Decreasing contact area of reactants

Decreasing the contact area of reactants would reduce the likelihood of collisions between them, leading to a slower reaction rate. This option is incorrect as it works against the principles of reaction kinetics.

B) Increasing the concentration of products

Increasing the concentration of products would not affect the rate of an endothermic reaction in a positive way. In fact, it could shift the equilibrium position, potentially slowing down the forward reaction, making this option incorrect.

C) Decreasing the temperature

Decreasing the temperature would lower the kinetic energy of the reactants, resulting in fewer effective collisions and a slower reaction rate. Therefore, this option is also incorrect as it contradicts the requirements for an endothermic reaction to proceed efficiently.

D) Increasing the concentration of reactants

Increasing the concentration of reactants provides more molecules available for reaction, thereby increasing the chances of effective collisions. This directly correlates with a higher reaction rate, making this option correct.

Conclusion

The correct answer is D, as increasing the concentration of reactants is essential for enhancing the reaction rate in an endothermic process. Options A, B, and C all either reduce the likelihood of effective collisions or hinder the reaction, which is why they are incorrect. Ultimately, understanding how concentration affects reaction rates is crucial for manipulating chemical reactions effectively.