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Topic: CHEMISTRY!!!URGENT pre-equilibria  (Read 5181 times)

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Offline ana77

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CHEMISTRY!!!URGENT pre-equilibria
« on: January 24, 2010, 07:09:32 PM »
5Br-(aq) + BrO3-(aq) + 6H+(aq)--> 3Br2(l) + 3H2O(l)

The above reaction is expected to obey the mechanism:
k1
BrO3-(aq) + H+(aq)<--> HBrO3(aq) Fast equilibrium
k-1
k2
HBrO3(aq) + H+(aq)<--> H2BrO3+(aq) Fast equilibrium
k-2
k3
H2BrO3+(aq) + Br-(aq)--> (Br-BrO2)(aq) + H2O(l) Slow

k4
(Br-BrO2)(aq) + 4H+(aq) + 4Br-(aq)--> products Fast
Choose, from the list below, correct expressions for the overall rate law which are completely consistent with the above mechanism.

Correct Incorrect -d[Br-]/dt = k[BrO3-][Br-][H+]2
Correct Incorrect k[Br-][BrO3-][H+]2 = -d[BrO3-]/dt
Correct Incorrect -d[Br-]/dt = k[Br-]2[BrO3-][H+]
Correct Incorrect -d[H+]/dt = k[H+]4
Correct Incorrect -d[BrO3-]/dt = k[BrO3-][Br-][H+]2
Correct Incorrect -d[H+]/dt = k[Br-]


For each of the given rate expressions choose the correct expression for the rate constant (k) from the list below.
A. k = 5x(k1k2k3/k_1k_2)
B. k = 5x(k1k2k3-k_1k_2)
C. k = k1-k_1
D. k = k3
E. k = 6x(k1k2k3/k_1k_2)
F. none of the above


A, B, C, D, E or F -d[BrO3-]/dt
A, B, C, D, E or F -d[H+]/dt
A, B, C, D, E or F -d[Br-]/dt

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