Meena is performing an experiment with two substances, X and Y. When she puts a few granules of X in Y, she decides to collect Z- the gas produced, into a balloon. When she leaves the balloon, it floats in the air. Which of the following can be the substances X, Y and Z?

Options

A. X: Tin, Y: Hydrochloric Acid, Z: Hydrogen
B. X: Mercury, Y: Nitric Acid, Z: Nitric Oxide
C. X: Copper, Y: Sulphuric Acid, Z: Hydrogen
D. X: Potassium Permanganate, Y: Hydrogen Peroxide, Z: Hydrogen

Answer

To solve the question regarding Meena's experiment with substances X, Y, and Z, we need to analyze the possible combinations of these substances based on the reactions they undergo.

### Step-by-Step Solution:

1. **Identify the Reaction**:
We need to find a combination of substances X and Y that produces a gas Z, which is capable of making a balloon float. The gas must be lighter than air, which suggests it could be hydrogen (H₂) or helium (He).

2. **Evaluate the First Option**:
- **Substance X**: Tin (Sn)
- **Substance Y**: Hydrochloric acid (HCl)
- **Gas Z**: Hydrogen (H₂)

**Reaction**:
When tin reacts with hydrochloric acid, the reaction is:
\[ \text{Sn} + 2\text{HCl} \rightarrow \text{SnCl}_2 + \text{H}_2 \]
This reaction produces hydrogen gas (H₂), which is lighter than air and can make a balloon float.

3. **Evaluate the Second Option**:
- **Substance X**: Mercury (Hg)
- **Substance Y**: Nitric acid (HNO₃)
- **Gas Z**: Nitric oxide (NO)

**Analysis**:
Mercury does not displace hydrogen from nitric acid because it is below hydrogen in the reactivity series. Therefore, this option is incorrect.

4. **Evaluate the Third Option**:
- **Substance X**: Copper (Cu)
- **Substance Y**: Sulfuric acid (H₂SO₄)
- **Gas Z**: Hydrogen (H₂)

**Analysis**:
Copper does not react with dilute sulfuric acid to produce hydrogen because it is also below hydrogen in the reactivity series. Even with concentrated sulfuric acid, the reaction produces sulfur dioxide (SO₂) instead of hydrogen. Thus, this option is incorrect.

5. **Evaluate the Fourth Option**:
- **Substance X**: Potassium permanganate (KMnO₄)
- **Substance Y**: Hydrogen peroxide (H₂O₂)
- **Gas Z**: Hydrogen (H₂)

**Reaction**:
The reaction between potassium permanganate and hydrogen peroxide produces oxygen gas (O₂), not hydrogen gas. Therefore, this option is also incorrect.

### Conclusion:
The only correct combination that produces a gas which can make a balloon float is:
- **X**: Tin (Sn)
- **Y**: Hydrochloric acid (HCl)
- **Z**: Hydrogen (H₂)

Thus, the correct answer is the **first option**.

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