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Topic: Deriving mechanisms from rate laws  (Read 1512 times)

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Offline Rutherford

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Deriving mechanisms from rate laws
« on: February 20, 2013, 03:24:31 PM »
Deriving rate laws from given mechanism is relatively easy, but the opposite process seems much more difficult.

Propose the mechanisms for the reaction given below. Prove that your mechanism is consistent with the experimentally observed rate law. Use proper approximations if necessary.

Oxidation of bromide ion by permanganate in acidic solution
2MnO4 + 10Br + 16H+ = 2Mn2+ + 5Br2 + 8H2O
а) at low concentrations of Br and H+
r = kc(MnO42(Br3(H+)
б) at high concentrations of Br and H+
r = kc(MnO4)с(Br)с(H+)
where с are the total concentrations of reactants. In both cases:
с(MnO4) <<с(Br), с(H+).


I searched on the net the derivation of mechanisms but couldn't find anything.
I know that I need to use the steady state approximation, but how? Where to start from  :-\?
Any hint, link or explanation would be very appreciated.

Offline Rutherford

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Re: Deriving mechanisms from rate laws
« Reply #1 on: February 23, 2013, 02:08:13 PM »
Can this be even found on the internet? I was searching and searching, but only deriving rate laws from mechanisms appears, not the opposite.
Could anyone refer me to some site where this is explained?

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