The decomposition of hydrogen peroxide is catalyzed by iodide ion. The catalyzed reaction is thought to proceed by a two-step mechanism: H 2 O 2 (aq) + I - (aq) → H 2 O(l) + IO - (aq) (slow) IO - (aq) + H 2 O 2 (aq) → H 2 O(l) + O 2 (g) + I - (aq) (fast) (b) Identify the intermediate, if any, in the mechanism.

welcome back everyone in this example, we have the decomposition of ozone in the atmosphere and its proposed to occur via the following two step mechanism. We need to identify what are intermediate here would be So we want to recall the definition first of an intermediate. And we should recall that an intermediate is going to be produced in one step of a reaction as a product. Whereas in another step of reaction it's going to be consumed as a reactant. And so we need to identify which of our re agents follows the action as an intermediate. So looking at step one of our mechanism, we have chlorine gas reacting with ozone gas to produce as a product, chlorine monoxide and oxygen gas. Moving on to step two are mechanism we have chlorine monoxide now listed as a reactant, which is being consumed along with the second reacting ozone to produce chlorine gas and two moles of oxygen gas. And so what we should recognize is the trend where Chlorine Monoxide First was produced as a product in step one. So produced as a product. Whereas in step two we can see that our chlorine monoxide is now consumed as a reactant to form chlorine gas and two moles of oxygen gas as now the products. And so we would say that because our chlorine monoxide followed this or these actions in our mechanism, we can say that therefore chlorine monoxide gas acts as the sorry, acts as the intermediate in our given mechanism. And so this statement here would be our final answer to complete this example as the properly identified intermediate in our reaction chlorine monoxide. So I hope that everything that I reviewed was clear, but if you have any questions, just leave them down below and I will see everyone in the next practice video.

Ch.14 - Chemical Kinetics

All textbooks

Brown 14th Edition

Ch.14 - Chemical Kinetics

Problem 72b

Previous problem

Next problem

Chapter 14, Problem 72b

The decomposition of hydrogen peroxide is catalyzed by iodide ion. The catalyzed reaction is thought to proceed by a two-step mechanism:
H₂O₂(aq) + I^-(aq) → H₂O(l) + IO^-(aq) (slow)
IO^-(aq) + H₂O₂(aq) → H₂O(l) + O₂(g) + I^-(aq) (fast)
(b) Identify the intermediate, if any, in the mechanism.

Verified step by step guidance

Step 1: Understand the concept of reaction intermediates. A reaction intermediate is a species that is produced in one step of a reaction mechanism and consumed in a subsequent step. It does not appear in the overall chemical equation for the reaction.

Step 2: Look at the given reaction mechanism. The first step produces H2O and IO-. The second step consumes IO- and produces H2O, O2, and I-.

Step 3: Identify the species that is produced in the first step and consumed in the second step. In this case, it is IO-.

Step 4: Confirm that this species does not appear in the overall chemical equation for the reaction. The overall equation is obtained by adding the two steps together and cancelling out any species that appear on both sides. In this case, IO- does not appear in the overall equation.

Step 5: Conclude that IO- is the reaction intermediate in this mechanism.

Verified Solution

Video duration:

This video solution was recommended by our tutors as helpful for the problem above.

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Reaction Mechanism

A reaction mechanism is a step-by-step description of how a chemical reaction occurs at the molecular level. It outlines the sequence of elementary steps that lead to the formation of products from reactants. Understanding the mechanism helps in identifying intermediates, which are species formed during the reaction but not present in the final products.

Intermediates

Intermediates are transient species that appear in the course of a reaction mechanism but do not appear in the overall balanced equation. They are formed in one step and consumed in a subsequent step. Identifying intermediates is crucial for understanding the pathway of the reaction and the role of catalysts.

Catalysis

Catalysis is the process by which the rate of a chemical reaction is increased by the presence of a catalyst, which is not consumed in the reaction. Catalysts work by providing an alternative pathway with a lower activation energy. In the given reaction, iodide ion acts as a catalyst, facilitating the decomposition of hydrogen peroxide through the formation of intermediates.

Recommended video:

Guided course