Question

The proposed mechanism for a reaction is

1. A (g) + B (g) = X (g) fast, equilibrium

2. X (g) + C (g)?Y (g) slow

3. Y (g)?D (g) fast

a. Write the overall equation

b. identify the intermediates (circle all that apply)

A

B

C

D

X

Y

c. determine the overall rate law for the reaction

Answer 1

a)   A + B <===> X

      X + C -----> Y

       Y ----> D

---------------------------

A + B + C ----> D

b) intermediates are the ones that are formed in one step and in the next step they are consumed. In this case X and Y.

c) v1= k1 [A][B]

    v2= k2 [X]

I call v1 to the direct reaction of the reaction 1, and v2 to the indirect reaction of the reaction 2.

this reaction is at equilibrium so v1=v2 -----> k1[A][B]=k2[X] ----->[X]= k1[A][B]/k2

v3= k3[X][C] -----> V= k3k1/k2 [A][B][C]= K[A][B][C]