Answer: The first step of the mechanism is the rate determining step.
Explanation:
In a mechanism of the reaction, the slow step in the mechanism determines the rate of the reaction.
For the given chemical reaction:
[tex]2A_2+B_2\rightarrow 2C[/tex]
The intermediate reaction of the mechanism follows:
Step 1: [tex]A_2+B_2\rightleftharpoons R+C;\text{ (very slow)}[/tex]
Step 2: [tex]A_2+R\rightarrow C;\text{ (fast)}[/tex]
As, step 1 is the slow step, it will determine the rate of the reaction and is the rate determining step.
Rate law for the reaction will be:
[tex]\text{Rate}=k[A_2][B_2][/tex]
Hence, the first step of the mechanism is the rate determining step.
