Which of the following statement is/are true?
I rate law Is an experimental fact while law of mass action is a theortical proposal.
rate law is more imformative than law of mass action for the development of mechanism
Rate law is always different from the expression of law of mass action
choose the correct option

Options

A. III and I
B. III and II
C. II and I
D. All of the above

Answer

To determine which of the statements provided in the question are true, we will analyze each statement related to the concepts of rate law and law of mass action.

### Step-by-Step Solution:

1. **Understanding Rate Law and Law of Mass Action:**
- **Rate Law:** The rate law expresses the relationship between the rate of a chemical reaction and the concentration of its reactants. It is determined experimentally and can vary depending on the reaction mechanism.
- **Law of Mass Action:** This law states that the rate of a reaction is proportional to the product of the concentrations of the reactants, each raised to the power of their stoichiometric coefficients. It is a theoretical concept.

2. **Analyzing Statement I:**
- **Statement I:** "Rate law is an experimental fact while law of mass action is a theoretical proposal."
- **Analysis:** This statement is true. The rate law is derived from experimental data, while the law of mass action is based on theoretical principles.

3. **Analyzing Statement II:**
- **Statement II:** "Rate law is more informative than law of mass action for the development of mechanism."
- **Analysis:** This statement is also true. The rate law provides insights into the reaction mechanism, including the order of the reaction and the rate-determining step, which cannot be inferred from the law of mass action alone.

4. **Analyzing Statement III:**
- **Statement III:** "Rate law is always different from the expression of law of mass action."
- **Analysis:** This statement is false. While the rate law and law of mass action can differ, they are not always different. In some cases, the rate law may match the law of mass action, especially for elementary reactions where stoichiometric coefficients correspond to the reaction orders.

5. **Conclusion:**
- The true statements are I and II. Therefore, the correct option includes these statements.

### Final Answer:
The correct statements are:
- I: True
- II: True
- III: False

Thus, the correct option is that statements I and II are true.

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