When the rate of reaction is independent of the concentration of reactant then the order of that chemical reaction is

Options

A. one
B. two
C. three
D. zero

Answer

To determine the order of a chemical reaction when the rate is independent of the concentration of the reactant, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Reaction Rate**: The rate of a chemical reaction is generally expressed as a function of the concentrations of the reactants. For a reaction involving a reactant A, the rate can be written as:
\[ \text{Rate} = k[A]^n \]
where \( k \) is the rate constant, \( [A] \) is the concentration of reactant A, and \( n \) is the order of the reaction.

2. **Independence from Concentration**: If the rate of the reaction is independent of the concentration of reactant A, this implies that changing the concentration of A does not affect the rate. Mathematically, this can be expressed as:
\[ \text{Rate} = k[A]^0 \]
Since any quantity raised to the power of 0 is 1, this simplifies to:
\[ \text{Rate} = k \]

3. **Determining the Order**: From the equation \( \text{Rate} = k[A]^0 \), we can see that the exponent \( n \) (which represents the order of the reaction) is 0. Therefore, the reaction is classified as a **zero-order reaction**.

4. **Conclusion**: When the rate of reaction is independent of the concentration of the reactant, the order of that chemical reaction is **zero**.

### Final Answer:
The order of the chemical reaction is **0** (zero-order reaction).

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