Copper sulphate is prepared by blowing a current of air through copper scrap and dilute `H_(2)SO_(4)`. Dilute `HNO_(3)` is also added`:`

Options

A. to oxidize copper to `Cu^(2+)` which then form `CuSO_(4)` with dilute `H_(2)SO_(4)`
B. to oxidise `Fe^(2+)` to ion (III) sulphate, which remains in solution after crystallisation of `CuSO_(4)`
C. to speed up the ionisation of `H_(2)SO_(4)` to give `SO_(4)^(2-)` ions
D. Which combines with `H_(2)SO_(4)` to give a very strong oxidising mixture and oxidise Cu to `Cu^(2+)`

Answer

To understand why dilute HNO3 is added during the preparation of copper sulfate (CuSO4) by blowing air through copper scrap and dilute H2SO4, we can break down the process into a series of steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- We start with copper scrap (Cu) and dilute sulfuric acid (H2SO4).
- We also introduce dilute nitric acid (HNO3) into the reaction.

2. **Understanding the Reaction**:
- The goal is to convert solid copper (Cu) into copper sulfate (CuSO4).
- Copper sulfate consists of copper ions (Cu²⁺) and sulfate ions (SO₄²⁻).

3. **Oxidation of Copper**:
- To form CuSO4, copper must be in the ionic form (Cu²⁺).
- The conversion of solid copper (Cu) to copper ions (Cu²⁺) is an oxidation reaction.

4. **Role of HNO3**:
- HNO3 is a strong oxidizing agent.
- When dilute HNO3 is added, it facilitates the oxidation of copper (Cu) to copper ions (Cu²⁺).
- The reaction can be represented as:
\[ \text{Cu (s)} + 2\text{HNO}_3 (aq) \rightarrow \text{Cu}^{2+} (aq) + 2\text{NO}_3^{-} (aq) + 2\text{H}^+ (aq) \]

5. **Formation of Copper Sulfate**:
- Once Cu²⁺ ions are formed, they can react with sulfate ions (SO₄²⁻) from the dilute sulfuric acid to form copper sulfate (CuSO4):
\[ \text{Cu}^{2+} (aq) + \text{SO}_4^{2-} (aq) \rightarrow \text{CuSO}_4 (aq) \]

6. **Conclusion**:
- Therefore, the addition of dilute HNO3 is essential for the oxidation of copper to Cu²⁺, which is necessary for the formation of copper sulfate (CuSO4) in the reaction.