The proposed mechanism for a reaction is
1) A(g) + B(g) `hArr ` X(g) [fast]
2) X(g) +C(g) `->` Y(g) [slow]
3) Y(g) `->` D(g) [fast]
What are the molecularity and the rate law for each step?
The overall reaction for these proposed mechanisms is:
A(g) + B(g) + C(g) -> D(g)
Y and X are the intermediates.
The proposed mechanism is not a single step reaction that gives rise in the formation of the intermediates.
For the rate law; order of reaction; molecularity
1.` r = k[A][B]` ; second order reaction; bimolecular
2. `r = k[X][C]` ; second order reaction; bimolecular
3. `r = k[Y]` ; first order reaction; unimolecular
However since it is noted that the second reaction is the slow reaction, it is called the rate determining step.