Substance X reacts with dilute HCl violently, Y reacts slowly while Z does not react at all. X, Y and Z could be respectively

Options

A. Cu, Al, Fe
B. Al, Na, Cu
C. Na, Cu, Fe
D. K, Al, Cu

Explanation

To solve the question, we need to identify substances X, Y, and Z based on their reactivity with dilute hydrochloric acid (HCl).

### Step-by-Step Solution:

1. **Understanding the Reactivity with HCl**:
- Substance X reacts violently with dilute HCl.
- Substance Y reacts slowly with dilute HCl.
- Substance Z does not react at all with dilute HCl.

2. **Analyzing Substance X**:
- Since X reacts violently, it must be a highly reactive metal. In the reactivity series, metals such as potassium (K), sodium (Na), and calcium (Ca) are known to react vigorously with acids.
- Therefore, X could be potassium or sodium.

3. **Analyzing Substance Y**:
- Substance Y reacts slowly with dilute HCl. This suggests that Y is a less reactive metal compared to X but still reactive enough to displace hydrogen from HCl.
- Metals like magnesium (Mg) or aluminum (Al) can react slowly with dilute acids, so Y could be either of these.

4. **Analyzing Substance Z**:
- Substance Z does not react at all with dilute HCl. This indicates that Z is a metal that is less reactive than hydrogen, such as copper (Cu), silver (Ag), or gold (Au).
- Therefore, Z could be copper or any other less reactive metal.

5. **Finalizing the Substances**:
- Based on the reactivity series:
- X could be sodium (Na) or potassium (K) (highly reactive).
- Y could be magnesium (Mg) or aluminum (Al) (moderately reactive).
- Z could be copper (Cu) or silver (Ag) (non-reactive with HCl).
- The most logical assignment based on the reactivity series is:
- X = Sodium (Na) (reacts violently)
- Y = Aluminum (Al) (reacts slowly)
- Z = Copper (Cu) (does not react)

### Conclusion:
Thus, the substances X, Y, and Z could be respectively Sodium (Na), Aluminum (Al), and Copper (Cu).

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