The decomposition of hydrogen peroxide in solution and in the presence of iodide ion was studied in laboratory, and the following mechanism proposed based on the experimental data.
H2O2 + I - = H2O + IO - (slow)
H2O2 + IO - = H2O + O2 + I - (fast)
Which one of the following statements is false?
a. The reaction is first order with respect to H2O2.
b. The reaction is first order with respect to I -
c. I - is a catalyst.
d. IO - is an intermediate.
e. More than one statement is false (or none of the statements are false).
I think its E (none are false)
I think it is b. From the wording of the question, it appears to me that I^- is a catalyst. If that is true, the concn I^- will not matter.
To determine which statement is false, let's evaluate each option based on the given mechanism:
a. The reaction is first order with respect to H2O2.
The mechanism does not provide any information about the order of the reaction with respect to H2O2. Therefore, this statement is not supported by the given mechanism, and it could be false.
b. The reaction is first order with respect to I-.
The slow step of the mechanism involves the reaction between H2O2 and I-, suggesting that I- participates in the rate-determining step. This indicates that the reaction is first order with respect to I-. Therefore, this statement is supported by the given mechanism and is likely true.
c. I- is a catalyst.
In the mechanism, I- is consumed in the slow step and is regenerated in the fast step. A catalyst is a substance that participates in a reaction but is not consumed in the overall reaction. Since I- is consumed in the proposed mechanism, it is not acting as a catalyst. Therefore, this statement is not supported by the given mechanism and could be false.
d. IO- is an intermediate.
An intermediate is a species that is formed in one step of the mechanism and consumed in a subsequent step, but does not appear in the overall balanced equation. Based on the mechanism, IO- is formed in the first step and consumed in the second step. Therefore, IO- can be considered an intermediate. This statement is supported by the given mechanism and is likely true.
e. More than one statement is false (or none of the statements are false).
Based on the analysis above, we have found that statements a and c could potentially be false. Therefore, more than one statement could be false. Hence, the correct answer is e. More than one statement is false.