Which of the following statements are applicable to a balanced chemical equation of an elementary reaction ?

Options

A. Order is same as molecularity
B. Order is less than the molecularity
C. Order is greater than the molecularity
D. Molecularity can never he zero

Explanation

To solve the question regarding which statements are applicable to a balanced chemical equation of an elementary reaction, we will analyze each option step by step.

### Step 1: Understanding Elementary Reactions
An elementary reaction is a single-step reaction where reactants convert directly to products in one step. The molecularity of an elementary reaction is defined as the number of reactant molecules involved in the reaction.

### Step 2: Analyzing the Options
Now, let's evaluate each of the given options:

**Option A: Order is same as molecularity.**
- For elementary reactions, the order of the reaction is indeed the same as the molecularity. This is because the rate law can be directly derived from the stoichiometry of the reaction. Therefore, this statement is **correct**.

**Option B: Order is less than molecularity.**
- This statement is incorrect for elementary reactions. Since the order is equal to the molecularity, it cannot be less than molecularity. Therefore, this statement is **incorrect**.

**Option C: Order is greater than molecularity.**
- Similar to option B, this statement is also incorrect. The order cannot be greater than molecularity for elementary reactions. Therefore, this statement is **incorrect**.

**Option D: Molecularity can never be zero.**
- This statement is true. Molecularity refers to the number of reactant molecules involved in the reaction, and it cannot be zero; otherwise, it implies that there are no reactants to react. Therefore, this statement is **correct**.

### Step 3: Conclusion
From the analysis above, we conclude that:
- **Correct statements**: A and D
- **Incorrect statements**: B and C

### Final Answer
The applicable statements to a balanced chemical equation of an elementary reaction are:
- A. Order is same as molecularity.
- D. Molecularity can never be zero.

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