For the reaction x_2+ y + z → xy + xz, it is found that the rate equation is rate = k [x_2][y]. which of the following might explain why the concentration of z has no effect on the rate?

a. the concentration of z is very small and the others are very large.
b. z must react in a step other than the rate determining step.
c. z is an intermediate.
d. the fraction of molecules of z that have very high energies is zero.
e. the activation energy for z to react is very low.

 C. Z is an intermediate.

Explanation:  The given reaction is

And the rate equation is rate =  k [X_2][Y]

From this, we can imply that either the concentration of Z is very small in comparison tot he other reactants or the reactant Z is an intermediate which is available only for the given small amount of time.

There can be various steps in the mechanism for the proposed reaction and Z can also react in any of the steps. It is not necessary that it should react in a step other than the rate determining step.

This might be possible that the activation energy for Z to react is very low But since it has made a new kind of product that is XZ, then the former cannot be true.

the increase of protons   hope this