## K and k

$K = \frac{k_{forward}}{k_{reverse}}$

Ashley McClearnen 1B
Posts: 59
Joined: Fri Sep 28, 2018 12:26 am

### K and k

Can someone please explain why K = k/k' for a multistep reaction?

Fayez Kanj
Posts: 62
Joined: Fri Sep 28, 2018 12:18 am
Been upvoted: 1 time

### Re: K and k

Hello!

if we have A + B ⇄ C + D, we can write these 2 reactions:

A + B → C + D . forward rate = k[A][B]

C + D → A + B backward rate = k'[C][D]

At equilibrium, since the forward rate = backwards rate, then k[A][B] = k'[C][D]. Rearranging this makes [C][D]/[A][B] = k/k' . This also equals K.

Thus, at equilibrium, K = k/k'

Hope this helps :)