Iron powder and powder of rust are taken in two containers X and Y respectively. Dilute sulphuric acid is added to both the containers. Then

Options

A. effervescence is observed in two containers.
B. effervescence is observed in case of X but not Y.
C. effervescence is observed in case of Y but not X.
D. no effervescence is observed in both cases.

Explanation

To solve the question, we need to analyze the reactions that occur when dilute sulfuric acid is added to iron powder in container X and rust powder in container Y.

### Step-by-Step Solution:

1. **Identify the substances in the containers:**
- Container X contains iron powder (Fe).
- Container Y contains rust powder (which is primarily iron(III) oxide, Fe₂O₃, and may contain water and other compounds).

2. **Understand the nature of the substances:**
- Iron (Fe) is an element and retains its properties.
- Rust is a compound formed from iron and oxygen, and it does not retain the properties of elemental iron.

3. **Add dilute sulfuric acid to both containers:**
- In container X (iron powder + dilute sulfuric acid):
- The reaction occurs as follows:
\[ \text{Fe} + \text{H}_2\text{SO}_4 \rightarrow \text{FeSO}_4 + \text{H}_2 \]
- This reaction produces iron(II) sulfate (FeSO₄) and hydrogen gas (H₂). The evolution of hydrogen gas can be observed as bubbles.

- In container Y (rust powder + dilute sulfuric acid):
- Since rust is a compound, it does not react with dilute sulfuric acid in the same way as elemental iron. The reaction is minimal or does not occur significantly:
\[ \text{Fe}_2\text{O}_3 + \text{H}_2\text{SO}_4 \text{ (no significant reaction)} \]
- Therefore, no hydrogen gas is liberated, and no observable reaction occurs.

4. **Conclusion:**
- In container X, effervescence (bubbles) is observed due to the liberation of hydrogen gas.
- In container Y, no effervescence is observed as rust does not react with dilute sulfuric acid to produce hydrogen gas.

5. **Final Answer:**
- Effervescence (bubbles) is observed in container X but not in container Y.