2NO(g) + Cl2(g) 2NOCl This reaction was studied at – 10ºC and the following data was obtained run [N — Chemical Kinetics Chemistry Question
Question
2NO(g) + Cl2(g) 2NOCl This reaction was studied at – 10ºC and the following data was obtained run [NO] [Cl ] r 1 0.10 0.10 0.18 2 0.10 0.20 0.35 3 0.20 0.20 1.40 [NO] and [Cl ] are the initial concentrations and r is the initial reaction rate. The overall order of the reaction is .................. (Round off to the Nearest Integer). 0 2 0 0 0 2 0 0
💡 Solution & Explanation
**Step 1: Set up the rate law equation** For the reaction 2NO(g) + Cl₂(g) → 2NOCl, the rate law is: r = k[NO]^m[Cl₂]^n where m and n are the orders with respect to NO and Cl₂. **Step 2: Find the order with respect to Cl₂ using Runs 1 and 2** [NO] is constant (0.10 M), [Cl₂] doubles (0.10 → 0.20 M), rate approximately doubles (0.18 → 0.35): r₂/r₁ = ([Cl₂]₂/[Cl₂]₁)^n 0.35/0.18 ≈ 1.94 ≈ 2 = (0.20/0.10)^n = 2^n Therefore, **n = 1** (first order in Cl₂) **Step 3: Find the order with respect to NO using Runs 2 and 3** [Cl₂] is constant (0.20 M), [NO] doubles (0.10 → 0.20 M), rate increases by factor of 4 (0.35 → 1.40): r₃/r₂ = ([NO]₃/[NO]₂)^m 1.40/0.35 = 4 = (0.20/0.10)^m = 2^m Therefore, **m = 2** (second order in NO) **Step 4: Calculate overall order** Overall order = m + n = 2 + 1 = **3** Therefore, the answer is 3.00.