A reaction is thought to be second order with respect to the concentration of carbon monoxide. What evidence would support this?
Answer options...
A. Changing the initial concentration would have no effect on the rate.
B. Any change in the initial concentration would cause a directly proportional change in the rate.
C. Reducing the initial concentration to one-third of the original value would decrease the rate to one-third of the original rate.
D. Doubling the initial concentration would increase the rate of the reaction by four times.
C. Reducing the initial concentration to one-third of the original value would decrease the rate to one-third of the original rate.
To determine if a reaction is second order with respect to the concentration of carbon monoxide, we need to analyze the relationship between the rate of the reaction and the concentration of carbon monoxide.
Option A states that changing the initial concentration would have no effect on the rate. If this were the case, it would suggest that the reaction is zero order with respect to the concentration of carbon monoxide, not second order. Therefore, Option A does not support the hypothesis of a second-order reaction.
Option B suggests that any change in the initial concentration would cause a directly proportional change in the rate. This would imply that the reaction is first order, not second order. Thus, Option B does not support the hypothesis of a second-order reaction.
Option C states that reducing the initial concentration to one-third of the original value would decrease the rate to one-third of the original rate. This is consistent with a second-order reaction. If the rate decreases proportionally when the concentration is reduced by the same factor, it indicates a second-order dependency. Therefore, Option C provides evidence supporting the hypothesis of a second-order reaction.
Option D suggests that doubling the initial concentration would increase the rate of the reaction by four times. This is consistent with a first-order reaction, where doubling the concentration doubles the rate. Therefore, Option D does not support the hypothesis of a second-order reaction.
Based on this analysis, the correct answer is C. Reducing the initial concentration to one-third of the original value would decrease the rate to one-third of the original rate, indicating a second-order dependency on the concentration of carbon monoxide.
The correct answer is D. Doubling the initial concentration would increase the rate of the reaction by four times.
This evidence supports the idea of the reaction being second order with respect to the concentration of carbon monoxide. In second-order reactions, doubling the initial concentration will result in a quadrupling of the rate of the reaction. This is because the rate is directly proportional to the square of the concentration for a second-order reaction. Option D describes this relationship, making it the correct choice.