Shown in the mechanism below is the catalyzed decomposition of hydrogen peroxide. Determine the catalyst/s and the reaction intermediate/s.

Step 1. H₂O₂ + 2 Br^- + 2 H⁺ → 2 H₂O + Br₂

Step 2. H₂O₂ + Br₂ → 2 Br^- + 2 H⁺ + O₂

Consider the following reaction mechanism: 

OCl^–(aq) + H₂O(l) ⇌ HOCl(aq) + OH^–(aq)       (fast equilibrium)

I^–(aq) + HOCl(aq) → HOI(aq) + Cl^–(aq)           (slow)

HOI(aq) + OH^–(aq) → H₂O(l) + OI^–(aq)           (fast)

Determine the catalyst and intermediate(s).

A. No catalyst, intermediate = HOCl, HOI, OH^–

B. No catalyst, intermediates = H₂O, HOCl, HOI, OH^–

C. Catalyst = H₂O, intermediates = HOCl, HOI, OH^–

D. Catalyst = H₂O, intermediate = HOCl, HOI

The reaction H₂(g) + I₂(g) → 2 HI(g) was thought to occur via a two-step mechanism:

Step 1: I₂(g) ⇌ 2 I(g) (fast equilibrium)
Step 2: 2 I(g) + H₂(g) → 2 HI(g) (slow)

Determine the rate law for the reaction.

What is the rate law for the overall reaction represented by the diagram below where the black circles are carbon and red circles are oxygen if the 2nd step is the rate-determining step?

Consider the reaction below:

A + C₂ → AC₂

The reaction is first-order in A and first-order in C₂.

Two mechanisms are proposed for the reaction: 

Mechanism 1 (single-step):

A + C₂ → AC₂  

Mechanism 2:

B + C₂ → BC + C slow

A + BC → AB + C fast

AB +  2 C → AC₂ + B fast

Are both mechanisms valid? If yes why? 

Identify the order of the reaction based on the energy diagram and proposed mechanism:

Step 1: AB + C → AC + B

Step 2: AC + B → ACB

Consider this three-step mechanism for a reaction:

Cl₂ (g) k₁⇌k₂ 2 Cl (g) Fast

Cl (g) + CHCl₃ (g) →k₃ HCl (g) + CCl₃ (g) Slow

Cl (g) + CCl₃ (g) →k₄ CCl₄ (g) Fast

c. What is the predicted rate law?