Which of the following metals does not give the following reaction? (M + water `rarr` oxide or hydroxide `+ H_(2 ))

Options

A. Iron
B. Sodium
C. Mercury
D. Magnesium

Answer

To determine which metal does not react with water to form an oxide or hydroxide and liberate hydrogen gas, we will analyze the behavior of the given metals: Sodium (Na), Magnesium (Mg), Iron (Fe), and Mercury (Hg).

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The reaction in question is:
\[ M + \text{water} \rightarrow \text{oxide or hydroxide} + H_2 \]
This indicates that the metal (M) reacts with water to produce either a metal oxide or hydroxide and hydrogen gas.

2. **Identifying the Metals**:
- **Sodium (Na)**: This is an alkali metal (Group 1). Alkali metals react vigorously with water to form hydroxides and liberate hydrogen gas.
- **Magnesium (Mg)**: This is an alkaline earth metal (Group 2). Magnesium reacts with water (more readily with steam) to form magnesium hydroxide and hydrogen gas.
- **Iron (Fe)**: This is a transition metal. Iron reacts with steam (not liquid water) to produce iron oxide and hydrogen gas.
- **Mercury (Hg)**: This is also a transition metal. Mercury does not react with water to form an oxide or hydroxide. It typically reacts with strong acids instead.

3. **Analyzing Each Metal's Reaction with Water**:
- **Sodium**: Reacts with water → Produces sodium hydroxide + \( H_2 \).
- **Magnesium**: Reacts with water (especially steam) → Produces magnesium hydroxide + \( H_2 \).
- **Iron**: Reacts with steam → Produces iron oxide + \( H_2 \).
- **Mercury**: Does not react with water at all.

4. **Conclusion**:
Based on the analysis, the metal that does not give the reaction \( M + \text{water} \rightarrow \text{oxide or hydroxide} + H_2 \) is **Mercury (Hg)**.

### Final Answer:
The metal that does not give the reaction is **Mercury (Hg)**.

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