Which of the following oxide is most acidic?

Options

A. `Na_2O `
B. `Al_2O_3
C. `P_2O_5`
D. `SO_3`

Answer

To determine which of the given oxides is the most acidic, we can follow these steps:

### Step 1: Identify the Oxides
The oxides given in the question are:
- Sodium oxide (Na2O)
- Aluminium oxide (Al2O3)
- Phosphorus oxide (P2O5)
- Sulfur trioxide (SO3)

### Step 2: Understand Acidic and Basic Nature of Oxides
In general, oxides can be classified as acidic, basic, or amphoteric based on the element's position in the periodic table:
- Basic oxides are typically formed by metals (e.g., Na2O).
- Acidic oxides are typically formed by non-metals (e.g., SO3).
- Amphoteric oxides can act as either acidic or basic (e.g., Al2O3).

### Step 3: Analyze the Oxides
- **Sodium oxide (Na2O)**: This is a basic oxide.
- **Aluminium oxide (Al2O3)**: This is amphoteric, meaning it can act as both an acid and a base.
- **Phosphorus oxide (P2O5)**: This is an acidic oxide.
- **Sulfur trioxide (SO3)**: This is a highly acidic oxide.

### Step 4: Compare the Acidity
From the analysis:
- Sodium oxide is basic.
- Aluminium oxide is amphoteric.
- Phosphorus oxide is acidic but less acidic than sulfur trioxide.
- Sulfur trioxide is known to be one of the most acidic oxides.

### Conclusion
Based on the above analysis, the most acidic oxide among the given options is **Sulfur trioxide (SO3)**.

### Final Answer
**Sulfur trioxide (SO3)** is the most acidic oxide.

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