Consider the gas-phase conversion of species X and Y to products according to the global equation
2 X(g) + Y(g) → products
A chemist suggests the following reaction pathway, in which the first step is known to be the slowest.
Step 1 (slow): 2 X → X₂‡ (‡ denotes an activated complex)
Step 2 (fast): X₂‡ + Y → products
(a) Derive the differential rate law expected for the overall reaction based on the mechanism.
(b) Identify the numerical value of each reactant’s kinetic order and the total reaction order.
(c) Describe qualitatively how the initial rate will change if the initial concentration of X is tripled while the concentration of Y is held constant.