Assertion (A) : The order of a reaction can be fractional but molecularity is never fractional.
Reason (R ): The order of reaction does not depend upon the stoichiometric coefficients of a balanced equation.

Options

A. If both `(A)` and `(R )` are correct, and `(R )` is the correct explnation of `(A)`.
B. If both `(A)` and `(R )` are correct, but `(R )` is noth the correct explanation of `(A)`.
C. If `(A)` is correct, but `(R )` is incorrect.
D. If `(A)` is incorrect, but `(R )` is correct.

Answer

To solve the question, we need to analyze the assertion and reason provided:

### Assertion (A):
The order of a reaction can be fractional but molecularity is never fractional.

### Reason (R):
The order of reaction does not depend upon the stoichiometric coefficients of a balanced equation.

### Step-by-Step Solution:

1. **Understanding Order of Reaction**:
- The order of a reaction is defined as the sum of the powers of the concentration terms in the rate law expression.
- It can be determined experimentally and can take on fractional values (e.g., 0.5, 1.5) as well as whole numbers (e.g., 1, 2, 3).

2. **Understanding Molecularity**:
- Molecularity refers to the number of reactant molecules involved in a single reaction step.
- It is always a whole number (1, 2, 3, etc.) and cannot be fractional. For example, a reaction involving two molecules has a molecularity of 2.

3. **Analysis of Assertion (A)**:
- The assertion states that the order of a reaction can be fractional while molecularity cannot. This is true because, as discussed, order can be determined from experimental data and can take on fractional values, whereas molecularity is strictly defined by the number of molecules involved in the reaction.

4. **Analysis of Reason (R)**:
- The reason states that the order of reaction does not depend on the stoichiometric coefficients of a balanced equation. This is also true. The order of reaction is determined by the mechanism of the reaction and the experimental data, not just the coefficients from the balanced equation.

5. **Conclusion**:
- Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct conclusion is that both statements are correct.

### Final Answer:
Both the assertion (A) and reason (R) are true, and the reason correctly explains the assertion.

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