[hope35]

This is more of a general chemistry question. But this is from my physical chemistry class so I thought I'll put it here. So here's the question:

A=CH₃COCH₃
I=CH₃COHCH₃⁺
E=CH₃COHCH₂
P=CH₃COCH₂Br

Using the following mechanism:

A + H⁺ I. With equilibrium constant "K"
I + H₂O  E + H₃O⁺. With k₁ going forward, and k_-1 going backwards.
E + Br₂  P + H+ + Br-. With  k₂ going forward.

I'm suppose to prove this: d[P]/dt =  k₁ k₂ K [A][H⁺][Br₂] / k_-1[H⁺] + k₂[Br₂].

I've tried solving this for a while and didn't quite get it. Here's what I did. Using the rate law, I know the formation of the product "P" is the rate constant times the reactant.

P=K₂ *[Br₂]*E
P=K₂ *[Br₂]*k₁ * I / k_-1 [H⁺]
P=K₂ *[Br₂]*k₁ * K*A*H⁺ / k_-1 [H⁺]

Doubt I did this right. But that's as far as I can go. Not sure how to get the other part: k₂[Br₂], into the proof. Anyone have any idea??

[Schrödinger]

You need to use steady state approximation. That way, you can easily find [E].
All you have to do is assume that the rate of formation on E = Rate of destruction of E.

After that, it should be quite easy.



You might wanna see this : http://en.wikipedia.org/wiki/Steady_state_%28chemistry%29