AIIMS 2017 Chemistry Rate Law MCQ Question

In the provided reaction mechanism, the slowest step is the first reaction (I), which involves the formation of 2NOBr from 2NO and Br₂. This step indicates that the rate of the overall reaction is dependent on the concentration of NO, leading to the rate law: Rate = k[NO]². Other options are incorrect because they either include species that do not participate in the rate-determining step (like NOBr₂) or suggest incorrect stoichiometric relationships that do not reflect the mechanism's kinetics. Understanding the rate law requires identifying the slowest step and the reactants involved in that step, which is crucial for predicting reaction rates accurately.