Aqueous solution of which of the following oxides turns blue litmus red?

Options

A. Sulphur dioxide
B. Magnesium oxide
C. Iron oxide
D. Copper oxide

Explanation

To determine which aqueous solution of the following oxides turns blue litmus red, we need to identify whether the oxides are acidic in nature. An acidic solution will turn blue litmus paper red.

**Step 1: Understand the nature of the oxides.**
- Oxides can be classified into two main categories: metal oxides and non-metal oxides.
- Non-metal oxides generally produce acidic solutions when dissolved in water, while metal oxides tend to produce basic solutions.

**Step 2: Analyze the options provided.**
- We need to look at the specific oxides given in the options to identify their nature.

**Step 3: Identify the oxides.**
1. **Sulfur dioxide (SO₂)**: This is a non-metal oxide. When dissolved in water, it forms sulfurous acid (H₂SO₃), which is acidic.
2. **Magnesium oxide (MgO)**: This is a metal oxide. It is basic when dissolved in water.
3. **Iron oxide (FeO)**: This is also a metal oxide. It is basic in nature.
4. **Copper oxide (CuO)**: This is another metal oxide. It is basic as well.

**Step 4: Conclusion.**
- Among the options, only sulfur dioxide (SO₂) is a non-metal oxide that produces an acidic solution. Therefore, it is the oxide that will turn blue litmus paper red.

**Final Answer: Sulfur dioxide (SO₂)**

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