Write balanced chemical equations for the preparation of the following salts in the laboratory:
A soluble sulphate by the action of an acid on insoluble metal oxide.

Explanation

To prepare a soluble sulfate by the action of an acid on an insoluble metal oxide, we can take copper oxide (CuO) as the insoluble metal oxide and sulfuric acid (H2SO4) as the acid. The balanced chemical equation for this reaction can be derived as follows:

### Step 1: Identify the reactants
- **Insoluble metal oxide**: Copper oxide (CuO)
- **Acid**: Sulfuric acid (H2SO4)

### Step 2: Write the reaction
When copper oxide reacts with sulfuric acid, it forms copper sulfate (CuSO4) and water (H2O).
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