A : when temperature becomes `oo` then the value of rate constant is maximum.
R : a is also known as maximum rate constant.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements , then mark (4)

Answer

To analyze the statements given in the question, we need to break down the concepts of the rate constant (k), the temperature (T), and the pre-exponential factor (A) in the context of chemical kinetics.

### Step-by-Step Solution:

1. **Understanding the Rate Constant (k)**:
The rate constant (k) is a crucial parameter in chemical kinetics that indicates the speed of a reaction. It is influenced by various factors, including temperature.

2. **Arrhenius Equation**:
The relationship between the rate constant (k) and temperature (T) is described by the Arrhenius equation:
\[ k = A e^{-\frac{E_a}{RT}} \]
where:
- \( A \) is the pre-exponential factor (also known as the frequency factor),
- \( E_a \) is the activation energy,
- \( R \) is the universal gas constant,
- \( T \) is the absolute temperature in Kelvin.

3. **Behavior of k as T Approaches Infinity**:
As the temperature (T) approaches infinity, the term \(-\frac{E_a}{RT}\) approaches zero because \( R \) and \( E_a \) are constants. Thus, we can evaluate the limit:
\[ \lim_{T \to \infty} k = A e^{0} = A \]
This indicates that the rate constant (k) approaches the value of the pre-exponential factor (A) as temperature increases indefinitely.

4. **Maximum Value of k**:
Since \( A \) is a constant that represents the maximum frequency of effective collisions in the reaction, we conclude that the maximum value of the rate constant (k) occurs when T is infinite, and this maximum value is equal to A.

5. **Conclusion**:
- Statement A is true: When temperature becomes infinite, the value of the rate constant (k) is indeed maximum.
- Statement R is also true: A is known as the maximum rate constant (or pre-exponential factor).

### Final Answer:
Both statements A and R are true, and the correct answer is that both statements are correct.