For a reaction `A+ B to ` Products, the rate law is -Rate `= k[A][B]^(3//2)`
Can the reaction be an elementray reaction ? Explain.

Explanation

To determine whether the reaction \( A + B \to \text{Products} \) can be classified as an elementary reaction based on the given rate law \( -\text{Rate} = k[A][B]^{3/2} \), we need to analyze the conditions for an elementary reaction.

### Step 1: Understand the Definition of Elementary Reactions
An elementary reaction is a single-step reaction where the rate law can be directly derived from the stoichiometry of the reaction. The two main conditions for an elementary reaction are:
1. The reaction must occur in a single step.
2. The order of the reaction must equal the molecularity of the reaction.

### Step 2: Analyze the Given Rate Law
The rate law provided is:
\[ -\text{Rate} = k[A][B]^{3/2} \]
From this rate law, we can determine the order of the reaction.

### Step 3: Calculate the Order of the Reaction
The order of the reaction is the sum of the powers of the concentration terms in the rate law. In this case:
- The order with respect to \( A \) is 1 (since the exponent of \( [A] \) is 1).
- The order with respect to \( B \) is \( \frac{3}{2} \) (since the exponent of \( [B] \) is \( \frac{3}{2} \)).

Thus, the total order of the reaction is:
\[ \text{Order} = 1 + \frac{3}{2} = \frac{5}{2} = 2.5 \]

### Step 4: Determine the Molecularity of the Reaction
The molecularity of a reaction is defined as the number of reactant molecules involved in the elementary step. In this case, we have:
- 1 molecule of \( A \)
- 1 molecule of \( B \)

Thus, the molecularity of the reaction is:
\[ \text{Molecularity} = 1 + 1 = 2 \]

### Step 5: Compare Order and Molecularity
Now, we compare the order of the reaction with its molecularity:
- Order of the reaction = 2.5
- Molecularity of the reaction = 2

Since the order of the reaction (2.5) does not equal the molecularity of the reaction (2), we conclude that the reaction cannot be an elementary reaction.

### Conclusion
Based on the analysis, the reaction \( A + B \to \text{Products} \) cannot be classified as an elementary reaction because the order of the reaction does not match its molecularity.

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