To determine which of the given oxides are acidic, we need to analyze the oxidation states of the elements in each oxide. Here’s a step-by-step solution:
### Step 1: Identify the Oxidation States
1. **CuO (Copper(II) oxide)**
- Let the oxidation state of Cu be \( x \).
- The equation is: \( x + (-2) = 0 \)
- Therefore, \( x = +2 \).
2. **Mn₂O₇ (Manganese(VII) oxide)**
- Let the oxidation state of Mn be \( x \).
- The equation is: \( 2x + (-14) = 0 \)
- Therefore, \( 2x = 14 \) leading to \( x = +7 \).
3. **CO (Carbon monoxide)**
- Let the oxidation state of C be \( x \).
- The equation is: \( x + (-2) = 0 \)
- Therefore, \( x = +2 \).
4. **SO₂ (Sulfur dioxide)**
- Let the oxidation state of S be \( x \).
- The equation is: \( x + 2(-2) = 0 \)
- Therefore, \( x - 4 = 0 \) leading to \( x = +4 \).
5. **CrO₃ (Chromium trioxide)**
- Let the oxidation state of Cr be \( x \).
- The equation is: \( x + 3(-2) = 0 \)
- Therefore, \( x - 6 = 0 \) leading to \( x = +6 \).
### Step 2: Determine the Acidity Based on Oxidation States
- Generally, oxides of non-metals and transition metals with high oxidation states tend to be acidic.
- **CuO** has an oxidation state of +2, which is relatively low for a metal oxide, making it basic.
- **Mn₂O₇** has an oxidation state of +7, which is high, indicating it is acidic.
- **CO** has an oxidation state of +2, indicating it is basic.
- **SO₂** has an oxidation state of +4, indicating it is acidic.
- **CrO₃** has an oxidation state of +6, indicating it is acidic.
### Step 3: Conclusion
Based on the analysis:
- Acidic oxides: **Mn₂O₇, SO₂, CrO₃**
- Basic oxides: **CuO, CO**
Thus, the acidic oxides among the options given are **Mn₂O₇, SO₂, and CrO₃**.
### Final Answer
The acidic oxides are **Mn₂O₇, SO₂, and CrO₃**.
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