## Rate-determining step

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

Eileen Si 1G
Posts: 120
Joined: Fri Aug 30, 2019 12:17 am

### Rate-determining step

How can you identify which step of the reaction mechanism is the slowest step? Or will this just be given in the problem itself?

MingdaH 3B
Posts: 133
Joined: Thu Jul 11, 2019 12:17 am

### Re: Rate-determining step

Identifying the rate limiting step can be proposed / guessed from the reaction rate equation. Depending on the question, it may also be given in the problem itself.

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: Rate-determining step

Usually the slow step will be given, but you might be given data about the different steps and have to analyze it to determine the rate determining step

Ayushi2011
Posts: 101
Joined: Wed Feb 27, 2019 12:17 am

### Re: Rate-determining step

They usually tell us which is the slow and fast step.

rabiasumar2E
Posts: 108
Joined: Thu Jul 11, 2019 12:15 am

### Re: Rate-determining step

It will probably be given to you in the question!

Esha Chawla 2E
Posts: 108
Joined: Thu Jul 25, 2019 12:17 am

### Re: Rate-determining step

Eileen Si 1G wrote:How can you identify which step of the reaction mechanism is the slowest step? Or will this just be given in the problem itself?

If you are given the differential rate law and a proposed reaction mechanism (with its elementary steps), you can determine which elementary step is rate-determining by seeing which elementary step has the proposed differential rate law. If you are not given the differential rate law, then you will likely be told which step is the slowest step, and you will (likely) have to determine the differential rate law.

005206171
Posts: 107
Joined: Wed Sep 18, 2019 12:20 am

### Re: Rate-determining step

If they give you a rate law and ask to find the rate determining step out of given elementary steps, look for the step that has all of the molecules in the given rate law/ match them.

Nathan Rothschild_2D
Posts: 131
Joined: Fri Aug 02, 2019 12:15 am

### Re: Rate-determining step

Isn't there a way to tell which is the rate determining step by looking at phases or am I just mistaken?