A chemical reaction involves two reacting species. The rate of reaction is directly proportional to the conc. Of one of them and inversely proportional to the concentration of the other. The order of reaction is

Options

A. zero
B. 1
C. 2
D. 4

Explanation

To determine the order of the reaction based on the information provided, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**:
We have a reaction involving two species, A and B.

2. **Understand the Rate Law**:
According to the problem, the rate of the reaction (R) is directly proportional to the concentration of one species (A) and inversely proportional to the concentration of the other species (B). This can be expressed mathematically as:
\[ R \propto \frac{[A]}{[B]} \]

3. **Formulate the Rate Equation**:
To convert the proportionality into an equation, we introduce a rate constant (k):
\[ R = k \cdot \frac{[A]}{[B]} \]

4. **Express the Rate in Terms of Concentrations**:
This can be rewritten as:
\[ R = k \cdot [A]^1 \cdot [B]^{-1} \]
Here, the exponent of [A] is 1 (indicating first order with respect to A) and the exponent of [B] is -1 (indicating inverse dependence, or negative order with respect to B).

5. **Calculate the Overall Order of the Reaction**:
The overall order of the reaction is the sum of the individual orders with respect to each reactant:
\[ \text{Overall Order} = 1 + (-1) = 0 \]

6. **Conclusion**:
Therefore, the overall order of the reaction is 0.

### Final Answer:
The order of the reaction is **0**.

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