Question

The rate-limiting step is the:

• A. Fastest step
• B. Slowest step
• C. Initial step
• D. Final step

Hint:

Think of a narrow bridge in a traffic jam — the slowest part limits the entire flow. That's how the slowest step limits the reaction rate.

Answer 1

The Correct Option is B

In a multi-step reaction mechanism, the rate-limiting step (also called the rate-determining step) is the slowest step in the sequence.
This step controls the overall reaction rate because the system must wait for it to complete before proceeding further. It acts like a bottleneck in the reaction pathway.
Even if other steps are faster, the overall reaction cannot proceed any quicker than the slowest one. Hence, the reaction rate is governed by the kinetics of this slowest step.
Therefore, the rate-limiting step is the slowest step in the reaction mechanism.