Consider the following energy profile.
(c) Which step is rate limiting?

Verified step by step guidance

1. Identify the highest energy transition state on the energy profile diagram.
2. Compare the energy of this transition state to the energies of other transition states in the reaction mechanism.
3. The step with the highest energy transition state is typically the slowest step in the reaction mechanism.
4. The slowest step in the reaction mechanism is considered the rate-limiting step because it determines the overall rate of the reaction.
5. Conclude that the step with the highest energy transition state is the rate-limiting step.

Key Concepts

Energy Profile Diagram

An energy profile diagram visually represents the energy changes during a chemical reaction. It typically shows the energy of reactants, products, and the transition states, illustrating the activation energy required for the reaction to proceed. Understanding this diagram is crucial for identifying the rate-limiting step, which is the slowest step in the reaction mechanism.

Activation Energy

Activation energy is the minimum energy required for reactants to undergo a chemical reaction. It is represented as the energy barrier that must be overcome for the transition state to form. The step with the highest activation energy in a reaction mechanism is often the rate-limiting step, as it dictates the overall speed of the reaction.

Rate-Limiting Step

The rate-limiting step is the slowest step in a reaction mechanism that determines the overall rate of the reaction. It acts as a bottleneck, meaning that even if other steps are faster, the rate of the entire process cannot exceed the rate of this step. Identifying the rate-limiting step is essential for understanding reaction kinetics and optimizing reaction conditions.