If the rate expression for a chemical reaction is given by Rate =`K[A]^n[B]^m` then

Options

A. The order of the reaction is m
B. The order of the reaction is n
C. The order of the reaction is m + n
D. The order of the reaction is m - n

Answer

To solve the question regarding the rate expression for a chemical reaction given by Rate = `K[A]^n[B]^m`, we need to determine the order of the reaction based on the provided rate law.

### Step-by-Step Solution:

1. **Understand the Rate Expression**: The rate expression is given as Rate = `K[A]^n[B]^m`, where:
- `K` is the rate constant.
- `[A]` and `[B]` are the concentrations of reactants A and B, respectively.
- `n` is the exponent for reactant A.
- `m` is the exponent for reactant B.

2. **Define Reaction Order**: The order of a reaction is defined as the sum of the powers of the concentration terms in the rate law expression. It indicates how the rate of reaction depends on the concentration of the reactants.

3. **Identify the Powers**: From the rate expression:
- The power of concentration for A is `n`.
- The power of concentration for B is `m`.

4. **Calculate the Total Order**: To find the overall order of the reaction, we add the powers of the concentrations:
\[ \text{Order of the reaction} = n + m \]

5. **Select the Correct Option**: Among the provided options:
- Option 1: Order of the reaction is m.
- Option 2: Order of the reaction is n.
- Option 3: Order of the reaction is m + n.
- Option 4: Order of the reaction is m - n.

The correct option that matches our calculation is **Option 3: Order of the reaction is m + n**.

### Final Answer:
The order of the reaction is **m + n**.

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