Consider the following overall reaction which is experimentally observed to be second order in AB and zero order in C:

AB+C -> A+BC

Determine whether the mechanism below is valid for this reaction
AB+ AB -> AB(sub 2) + A slow
AB(sub2) + C -> AB+BC fast

Well, this mechanism certainly seems entertaining! But let's see if it's valid for the given reaction.

Based on the overall reaction, we observe that AB + C produces A + BC. So, let's see if the proposed mechanism leads to the same overall reaction.

In the first step, AB + AB -> AB2 + A is a slow step. This step is not consistent with the experimental observation that the overall reaction is second order in AB. In this proposed step, two molecules of AB are reacting to form one molecule of AB2 and one molecule of A. This would imply that the reaction is first order in AB, not second order. So, this first step doesn't match the observed behavior.

In the second step, AB2 + C -> AB + BC is a fast step. This step is consistent with the observed zero order in C, as it does not involve C in the rate-determining step. However, this step doesn't address the issue we found in the first step.

Therefore, based on the inconsistency with the observed second order in AB, the proposed mechanism is not valid for this reaction. It looks like this reaction needs a different mechanism to explain its behavior.

But hey, don't worry! Chemistry can be tricky sometimes, just like trying to fit a giant balloon into a tiny car. It's all about finding the right pieces! Keep exploring, and you'll find the mechanism that fits like a glove!

To determine if the proposed mechanism is valid for the given reaction, we need to compare the rate law predicted by the mechanism with the experimentally observed rate law.

The overall reaction is described as second order in AB and zero order in C. This means that the rate of the reaction depends on the concentration of AB squared ([AB]^2) and is independent of the concentration of C. Let's analyze the proposed mechanism step by step:

Step 1: AB + AB -> AB2 + A (slow)
This step involves the collision of two AB molecules to form AB2 and A. The rate-determining step of a mechanism is usually the slowest step, determining the overall rate of the reaction. However, this step involves two AB molecules, so it cannot explain the observed zero order in C.

Step 2: AB2 + C -> AB + BC (fast)
This step involves the reaction between AB2 and C to form AB and BC. Since it is described as a fast step, it does not contribute to the overall rate law.

Based on the proposed mechanism, the rate-determining step (Step 1) does not account for the observed zero order in C. Therefore, the proposed mechanism is not valid for this reaction.

Keep in mind that this analysis assumes that the rate expressions for the individual steps involve elementary rate laws and that the proposed mechanism is the only possible pathway for the reaction to proceed.

To determine whether the proposed mechanism is valid for the given reaction, we need to check if it follows the observed rate law of the reaction, which is second order in AB and zero order in C.

In the proposed mechanism, there are two elementary steps:
1. AB + AB -> AB₂ + A (slow)
2. AB₂ + C -> AB + BC (fast)

Let's analyze the mechanism based on these elementary steps:

Step 1: AB + AB -> AB₂ + A (slow)
This step involves two molecules of AB reacting to form AB₂ and A. As this step is slow, it will be the rate-determining step.

The rate law expression for this step can be determined by considering the stoichiometry of the reactants:
Rate₁ = k₁ [AB]²

Step 2: AB₂ + C -> AB + BC (fast)
This step involves AB₂ reacting with C to form AB and BC. However, this step is fast and does not have a significant influence on the overall rate of the reaction.

Based on the proposed mechanism, the rate-determining step (Step 1) involves the concentration of AB squared, which matches the observed rate law being second order in AB. Therefore, the proposed mechanism is consistent with the observed rate law.

Hence, the mechanism is valid for the given reaction.

For this question you must fallow the 2 main rules of mechanisms. 1)The slowest elementary (RDS)step must match the rate law of the given rate law. 2)The mechanisms must match the given reaction after crossing out the intermediates of the reactions in the mechanisms.