True statement is

Options

A. poistive catalyst increases the rate of reaction.
B. During the course of the reaction, specific reaction rate remains constant.
C. Rate constant always increases with rise in temperature whether the reaction is endothermic or exothermic.
D. All are correct.

Answer

To determine which statements are true regarding chemical kinetics, let's analyze each statement step by step:

### Step 1: Analyze the first statement
**Statement A:** Positive catalysts increase the rate of reaction.

- **Explanation:** A positive catalyst, by definition, is a substance that increases the rate of a chemical reaction without being consumed in the process. Therefore, this statement is true.

### Step 2: Analyze the second statement
**Statement B:** During the course of a reaction, the specific reaction rate remains constant.

- **Explanation:** The specific reaction rate, often represented as the rate constant (k), does remain constant during the course of a reaction at a given temperature. It only changes when the temperature changes. Therefore, this statement is also true.

### Step 3: Analyze the third statement
**Statement C:** The rate constant always increases with a rise in temperature, whether the reaction is endothermic or exothermic.

- **Explanation:** According to the Arrhenius equation, the rate constant (k) increases with an increase in temperature (T). This is true for both endothermic and exothermic reactions. Therefore, this statement is true as well.

### Step 4: Analyze the final statement
**Statement D:** All are correct.

- **Explanation:** Since we have established that statements A, B, and C are all true, statement D, which claims that all previous statements are correct, is also true.

### Conclusion
Based on the analysis, the true statement is:
**Answer:** All of these (Option D).

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