Consider the gas-phase reaction: H2(g) + I2(g) → 2 HI(g)
The reaction was experimentally determined to be first order in H2 and first order in I2. Consider the proposed mechanisms.
Proposed mechanism I: H2(g) + I2(g) → 2 HI(g) Single step
Proposed mechanism II:
I2(g) → 2 I(g) Fast
H2(g) + 2 I(g) → 2 HI(g) Slow
Is the second of the proposed mechanisms valid?