STATEMENT -1 : During a chemical reaction, total mass remains constant.
and
STATEMETN -2 : Moles may vary in a reaction.

Options

A. Statement -1 is True, Statement -2 is True, Statement -2 is a correct explanation for Statmenet -1.
B. Statement -1 is True, Statement -2 is True, Statement-2 is NOT a correct explanation for Statement -1
C. Statement -1 is True, Statement -2 is False
D. Statement -1 is False, Statmenet -2 is True

Answer

To analyze the given statements, we will break down the concepts of mass conservation and the variation of moles during a chemical reaction.

### Step-by-Step Solution:

1. **Understanding Statement 1**:
- The first statement claims that "During a chemical reaction, total mass remains constant."
- This is a reflection of the Law of Conservation of Mass, which states that mass cannot be created or destroyed in a chemical reaction. Therefore, the mass of the reactants must equal the mass of the products.

2. **Example for Statement 1**:
- Consider the reaction of nitrogen (N2) and hydrogen (H2) to form ammonia (NH3):
\[ N_2 + 3H_2 \rightarrow 2NH_3 \]
- Balancing the equation, we find:
- 1 mole of N2 (mass = 28 g) + 3 moles of H2 (mass = 6 g) = 34 g
- Producing 2 moles of NH3 (mass = 34 g)
- Total mass before the reaction (reactants) = Total mass after the reaction (products) = 34 g.
- Thus, Statement 1 is **True**.

3. **Understanding Statement 2**:
- The second statement claims that "Moles may vary in a reaction."
- This means that the number of moles of reactants does not necessarily equal the number of moles of products.

4. **Example for Statement 2**:
- In the same reaction:
- Reactants: 1 mole of N2 + 3 moles of H2 = 4 moles
- Products: 2 moles of NH3
- Here, the number of moles changes from 4 moles of reactants to 2 moles of products.
- Therefore, Statement 2 is also **True**.

5. **Analyzing the Relationship**:
- While both statements are true, Statement 2 does not explain Statement 1. The conservation of mass is independent of the number of moles of reactants and products.
- Therefore, Statement 2 does not serve as a correct explanation for Statement 1.

6. **Conclusion**:
- Based on the analysis, we can conclude:
- Statement 1 is true.
- Statement 2 is true, but it does not explain Statement 1.
- The correct option is that Statement 1 is true, Statement 2 is true, but Statement 2 is not the correct explanation for Statement 1.

### Final Answer:
- Statement 1 is true, Statement 2 is true, but Statement 2 is not the correct explanation for Statement 1.