# Involving Rate determining steps

Foon
I have no idea how to figure this one out, I've been hacking away at it all evening. Please help Consider the general reaction:

2A + B --> 2E + F

The experimentally determined rate law equation is written as follows:

Rate = k[A]

A proposed mechanism for the reaction has the first step below:

Step 1: A + B --> C + F (rate determinging step)

Assuming a two-step mechanism, write a possible second elementary reaction for this mechanism.

And this is what I have but I'm not sure if its right. And I'm totally puzzled as to how they get rid of the C.

Step1: A + B --> C + F
Step2: A --> C- + 2E
------------------------
2A + B --> 2E + F

It has to be totally wrong since they've given me a rate law which I have no idea how to use.

## Answers and Replies

Homework Helper
Gold Member
HW, so this is going to be a step at a time: 1) what's the ORDER of the reaction --- you've got a rate expression; 2) what else does the rate expression tell you; 3) WHAT is "C"?

Meninger
You're almost there. For the second equation put C on the left side. That should do it.

sven222
Do what meninger said. C is the intermediate in the reaction, therefore it can't be in the final product at all.