In copper turnings test, pieces of copper is added to a nitrate salt and heated with conc. `H_(2)SO_(4)` .In this reaction copper acts as

Options

A. oxidising agent
B. dehydrating agent
C. reducing agent
D. bleaching agent

Explanation

To answer the question regarding the role of copper in the copper turnings test when heated with concentrated sulfuric acid and a nitrate salt, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding the Copper Turnings Test**:
- The copper turnings test is used to identify the presence of nitrate ions in a solution. This is done by adding copper turnings to a nitrate salt and heating it with concentrated sulfuric acid.

2. **Reaction Setup**:
- When copper turnings (Cu) are added to a nitrate salt (for example, sodium nitrate, NaNO3) and heated with concentrated sulfuric acid (H2SO4), a chemical reaction occurs.

3. **Chemical Reaction**:
- The concentrated sulfuric acid reacts with the nitrate salt to produce nitric acid (HNO3) and sodium bisulfate (NaHSO4):
\[ \text{NaNO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{NaHSO}_4 + \text{HNO}_3 \]
- The nitric acid then reacts with copper:
\[ \text{Cu} + 4 \text{HNO}_3 \rightarrow \text{Cu(NO}_3\text{)}_2 + 2 \text{NO}_2 + 2 \text{H}_2\text{O} \]

4. **Oxidation State Changes**:
- In this reaction, the oxidation state of copper changes from 0 (in elemental copper) to +2 (in copper(II) nitrate). This indicates that copper is losing electrons.

5. **Identifying the Role of Copper**:
- Since copper is losing electrons during the reaction, it is undergoing oxidation. In chemical terms, a substance that loses electrons is known as a reducing agent because it reduces another species (in this case, the nitrate ion) by donating electrons.

6. **Conclusion**:
- Therefore, in the copper turnings test, copper acts as a **reducing agent**.

### Final Answer:
In the copper turnings test, copper acts as a **reducing agent**.

---