Which of the following metals will not react dilute hydrochloric acid?

Options

A. Cu
B. Zn
C. Fe
D. Ca

Answer

To determine which of the following metals will not react with dilute hydrochloric acid (HCl), we need to analyze the reactivity of each metal in relation to hydrogen, as the reaction involves the replacement of hydrogen by the metal.

### Step-by-Step Solution:

1. **Identify the Metals**: The metals given in the question are Copper (Cu), Zinc (Zn), Iron (Fe), and Calcium (Ca).

2. **Understand the Reaction**: When a metal (M) reacts with dilute hydrochloric acid, it forms a metal chloride (MCl) and hydrogen gas (H₂):
\[ M + 2HCl \rightarrow MCl_2 + H_2 \]
In this reaction, the metal must be more reactive than hydrogen to replace it from the acid.

3. **Refer to the Reactivity Series**: The reactivity series ranks metals based on their ability to displace hydrogen. Metals that are above hydrogen in the series can displace it, while those below cannot.

4. **Locate Each Metal in the Reactivity Series**:
- **Copper (Cu)**: Located below hydrogen in the reactivity series, indicating it is less reactive than hydrogen.
- **Zinc (Zn)**: Located above hydrogen, indicating it is more reactive than hydrogen.
- **Iron (Fe)**: Also located above hydrogen, indicating it is more reactive than hydrogen.
- **Calcium (Ca)**: Located above hydrogen, indicating it is more reactive than hydrogen.

5. **Determine Reactivity**:
- **Cu + HCl**: No reaction (Cu is less reactive than H).
- **Zn + HCl**: Reaction occurs (Zn is more reactive than H).
- **Fe + HCl**: Reaction occurs (Fe is more reactive than H).
- **Ca + HCl**: Reaction occurs (Ca is more reactive than H).

6. **Conclusion**: The only metal that does not react with dilute hydrochloric acid is Copper (Cu).

### Final Answer:
**Copper (Cu) will not react with dilute hydrochloric acid.**

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