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?
A reaction mechanism is a step-by-step sequence of elementary reactions by which overall chemical change occurs. Information about a reaction mechanism is often obtained through the use of chemical kinetics.
To solve this problem, we will go through the following steps:
First, let’s see if the two equations in mechanism II add up to a balanced chemical equation.