When CuO reacts with hydrogen, .............. is reduced and ........... is oxidized to ..............

Answer

To answer the question "When CuO reacts with hydrogen, .............. is reduced and ........... is oxidized to ..............", we can break down the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this reaction are Copper(II) oxide (CuO) and hydrogen (H2).

2. **Determine the Products**: When CuO reacts with hydrogen, the products formed are copper (Cu) and water (H2O).

3. **Analyze Oxidation States**:
- In CuO, the oxidation state of copper (Cu) is +2 (since oxygen is -2).
- In the product (Cu), the oxidation state of copper is 0 (as it is a free element).
- Therefore, copper is being reduced from +2 to 0.

4. **Identify the Oxidation of Hydrogen**:
- In the reactant (H2), the oxidation state of hydrogen is 0 (as it is a free element).
- In the product (H2O), the oxidation state of hydrogen is +1.
- Therefore, hydrogen is being oxidized from 0 to +1.

5. **Final Statement**:
- CuO is reduced (Cu from +2 to 0).
- H2 is oxidized to H2O (H from 0 to +1).

### Final Answer:
When CuO reacts with hydrogen, **CuO** is reduced and **H2** is oxidized to **H2O**.

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