Consider the reaction
2 X2Y+Z2 ⇌ 2 X2YZ
which has a rate law of
rate= k[X2Y][Z2]
Select a possible mechanism for the reaction.
A possible mechanism for the reaction is:
X2Y + Z2 → X2YZ + X2YZ (fast)
X2YZ + X2Y → 2X2YZ (slow)
To select a possible mechanism for the given reaction, we need to consider the stoichiometry of the reaction and the rate law. In this case, the stoichiometry indicates that two molecules of X2Y are reacting with one molecule of Z2 to form two molecules of X2YZ.
Based on this information, a possible mechanism for the reaction could involve the following steps:
1. Reactant Z2 dissociates into two Z radicals:
Z2 ⇌ 2 Z•
2. Two X2Y molecules react with one Z radical each to form two XYZ radicals:
X2Y + Z• → XYZ + Y•
3. Two XYZ radicals combine to form X2YZ product:
XYZ + XYZ → X2YZ
Overall, this mechanism involves the formation and reaction of radicals. The rate-determining step would be the step involving the formation of XYZ radicals in step 2, as indicated by the rate law (rate = k[X2Y][Z2]). However, it is important to note that this mechanism is just one possible explanation and other mechanisms may also be possible. Experimental evidence would be needed to validate the proposed mechanism.
To determine a possible mechanism for the reaction, let's analyze the given reaction and the rate law.
Reaction: 2 X2Y + Z2 ⇌ 2 X2YZ
Rate Law: rate = k[X2Y][Z2]
Based on the reaction and the rate law, we can propose a possible mechanism as follows:
1. Step 1: Formation of an intermediate complex
X2Y + Z2 ⇌ X2YZ-Z2 (fast equilibrium)
2. Step 2: Rate-determining step (slow step)
X2YZ-Z2 + X2Y ⇌ X2YZ + X2Y-Z2 (fast equilibrium)
Note that in step 1, an intermediate complex X2YZ-Z2 is formed due to the collision between X2Y and Z2. This is an important step to establish the reaction mechanism.
In step 2, the rate-determining step, the intermediate complex reacts with another X2Y molecule to form the desired product X2YZ. At the same time, an X2Y-Z2 complex is formed, which can react back to regenerate the intermediate complex.
Overall, this proposed mechanism consists of a reversible formation of an intermediate complex followed by a rate-determining step involving the reaction between the intermediate and another reactant.