Question

For each reaction mechanism, identify the rate-determining step: step 1: no(g) cl2(g) nocl2(g) (fast) step 2: nocl2(g) no(g) 2nocl(g) (slow) step 1: h2o2(aq) i-(aq) hoi(aq) oh -(aq) (slow) step 2: hoi(aq) i -(aq) i2(aq) oh -(aq) (fast)

Answer 1

The rate-determining step is the slowest step in a reaction mechanism and determines the overall rate of the reaction.

Step-by-step explanation:

The rate-determining step is the slowest step in a reaction mechanism and determines the overall rate of the reaction. In the first mechanism provided, step 2 is the slow step, so it is the rate-determining step. In the second mechanism, step 3 is the slow step, so it is the rate-determining step. In the third mechanism, step 2 is the slow step, so it is the rate-determining step.

Answer 2

The rate-determining step is the slowest step in a reaction mechanism that controls the overall reaction rate. For the given mechanisms, the slow steps are identified, and the rate laws are determined by these slow steps in the sequence of reactions.

Step-by-step explanation:

In chemical kinetics, the rate-determining step is the slowest step of a reaction mechanism that dictates the overall rate of the reaction. For a reaction occurring in multiple steps, the rate law is typically governed by this slowest step. In the provided mechanisms, the rate-determining step is clearly labeled as 'slow' for each case.

• For the reaction mechanism involving NO and Cl₂, the rate-determining step is Step 2, which could be written as: rate = k [NOC1₂ ][NO]. The overall reaction is determined by adding the elementary steps and is 2NO(g) + Cl₂ (g) → 2NOCI(g).
• For the proposed mechanism of the reaction between NO and H₂, the rate-determining step is not explicitly stated, but can be inferred based on the provided data or experimental rate law.
• For the phosgene formation reaction CO with Cl₂, the rate-determining step is the slow step where CO reacts with Cl: rate = k₂ [CO][Cl]. The overall reaction is CO(g) + Cl₂ (g) → COCl₂ (g).