Which oxide is most acidic :-

Options

A. `Al_(2)O_(3)`
B. `Na_(2)O`
C. MgO
D. CaO

Answer

To determine which oxide is the most acidic among Al2O3, Na2O, MgO, and CaO, we can follow these steps:

### Step 1: Identify the Oxides
The oxides given in the question are:
- Sodium oxide (Na2O)
- Magnesium oxide (MgO)
- Calcium oxide (CaO)
- Aluminum oxide (Al2O3)

### Step 2: Classify the Oxides
Next, we classify these oxides based on the elements they are derived from:
- **Na2O**: Sodium is an alkali metal (Group 1).
- **MgO**: Magnesium is an alkaline earth metal (Group 2).
- **CaO**: Calcium is also an alkaline earth metal (Group 2).
- **Al2O3**: Aluminum is a post-transition metal (Group 13).

### Step 3: Determine the Acid-Base Nature
Now, we need to analyze the acid-base nature of these oxides:
- **Na2O, MgO, and CaO**: These oxides are typically basic in nature because they are derived from metals. They react with acids to form salts and water.
- **Al2O3**: Aluminum oxide has amphoteric properties, meaning it can react with both acids and bases. However, it is more acidic compared to the basic oxides mentioned above.

### Step 4: Conclusion
Based on the classification and acid-base nature:
- Sodium oxide (Na2O), magnesium oxide (MgO), and calcium oxide (CaO) are basic.
- Aluminum oxide (Al2O3) is more acidic than the other three oxides.

Thus, the most acidic oxide among the given options is **Al2O3**.

### Final Answer
**Al2O3** is the most acidic oxide among the given options.

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