Question

In experiments on the reaction 2 ICl(g) + ₂(g) → 1₂(g) + 2HCl(g), the following initial rate data were obtained. What is overall order of the reaction?

Experiment ICI M H₂ M Initial Rate, M/s
1 1.5 1.5 3.7 ×10⁻⁷
2 3.0 1.5 15 ×10⁻⁷
3 3.0 4.5 134 ×10⁻⁷

Answer 1

The overall order of the reaction 2 ICl(g) + H₂(g) → I₂(g) + 2 HCl(g) is determined to be fourth order by analyzing how changes in the concentration of reactants affect the initial rate, using given experimental data.

Step-by-step explanation:

To determine the overall order of the reaction, we need to analyze how changes in the concentration of reactants affect the reaction rate. Let's examine the provided initial rate data for the reaction 2 ICl(g) + H₂(g) → I₂(g) + 2 HCl(g).

• When the concentration of ICl is doubled (experiments 1 and 2), while H₂ is kept constant, the initial rate increases by a factor of 4 (from 3.7×10⁻⁷ to 15×10⁻⁷). This suggests that the reaction is second order with respect to ICl.
• When the concentration of H₂ is tripled (experiments 2 and 3), while ICl is kept constant, the initial rate increases by a factor of around 9 (from 15×10⁻⁷ to 134×10⁻⁷). This suggests that the reaction is second order with respect to H₂.

Therefore, the overall reaction order is the sum of the individual orders: 2 (ICl) + 2 (H₂) = 4. Hence, the overall order of the reaction is fourth order.