Which of the following oxides is most acidic in nature?

Options

A. MgO
B. BeO
C. BaO
D. CaO

Explanation

To determine which of the given oxides is most acidic in nature, we will analyze the options provided: magnesium oxide (MgO), beryllium oxide (BeO), barium oxide (BaO), and calcium oxide (CaO). All these oxides are derived from Group 2 elements (alkaline earth metals).

### Step-by-Step Solution:

1. **Identify the Oxides and Their Elements**:
- Option A: Magnesium oxide (MgO)
- Option B: Beryllium oxide (BeO)
- Option C: Barium oxide (BaO)
- Option D: Calcium oxide (CaO)

2. **Understand the Nature of Metal Oxides**:
- Generally, metal oxides are basic in nature. As we move down the group in the periodic table, the metallic character increases, leading to an increase in basicity.

3. **Analyze the Basicity of Each Oxide**:
- **Barium oxide (BaO)**: Being from the bottom of the group, it is highly basic.
- **Calcium oxide (CaO)**: Less basic than BaO but still basic.
- **Magnesium oxide (MgO)**: Less basic than CaO.
- **Beryllium oxide (BeO)**: It is unique among these oxides as it exhibits amphoteric behavior, meaning it can react with both acids and bases.

4. **Determine the Acidic Nature**:
- Since basicity increases down the group, the oxide with the lowest basicity will have the highest acidity. Therefore, BeO, which is amphoteric, will have the highest acidic nature compared to the other oxides.
- The other oxides (MgO, CaO, BaO) are primarily basic and do not exhibit acidic properties.

5. **Conclusion**:
- Based on the analysis, **Beryllium oxide (BeO)** is the most acidic in nature among the given options.

### Final Answer:
The oxide that is most acidic in nature is **Beryllium oxide (BeO)**.

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