At 500K, the homogeneous gas-phase oxidation of hydrogen is found experimentally to obey the rate law
rate=k[H2]0.5[O2].
A researcher suggests that the process might occur in a single elementary reaction.
Evaluate this suggestion.
(a) Show, by logical argument involving stoichiometric principles, that no one-step elementary reaction can yield the fractional orders observed in the rate law.
(b) Propose a mechanistic explanation—other than a single elementary step—that could account for the appearance of the fractional exponents in the empirical rate law.
(c) Explain how additional kinetic experiments (beyond initial-rate measurements) could be designed to distinguish between your proposed mechanism in part (b) and any alternative termolecular elementary step.