Question

How do you know the rate determining step?

Answer 1

There are many ways. However, in most general chemistry classes, this will suffice.

It's basically like the "bottleneck" of the reaction. For instance,

• If there is a slow, first step, that is the rate-determining step.
• If there is a fast, reversible first step, but a slow second step, then it's a tad more complicated. Here's a simple demonstration

`A + B rightleftharpoons C` `("fast")`
`C + D to E` `("slow")`
`E + D to F`

`k_1[A][B] = k_(-1)[C]`
`[C] = (k_1k_2)/(k_-1)[A][B]`

Therefore the rate law is,

`"R(t)" = (k_2k_1)/(k_-1)[A][B][D]`