What is the use of `CuSO_4` in kjeledahl's method ?

Options

A. Hydrolysing agent
B. Reducing agent
C. Oxidising agent
D. Catalytic agent

Answer

### Step-by-Step Solution:

1. **Understanding Kjeldahl's Method**:
- Kjeldahl's method is a widely used procedure for determining the nitrogen content in organic compounds. It involves the digestion of the sample with sulfuric acid (H2SO4) in the presence of a catalyst.

2. **Role of Copper Sulfate (CuSO4)**:
- In this method, copper sulfate (CuSO4) is added as a catalyst. The primary purpose of a catalyst is to increase the rate of a chemical reaction without being consumed in the process.

3. **Chemical Reaction**:
- During the digestion process, the organic nitrogen compounds are converted into ammonium sulfate (NH4)2SO4. The presence of CuSO4 facilitates this conversion by enhancing the efficiency of the reaction.

4. **Conclusion**:
- Therefore, the use of CuSO4 in Kjeldahl's method is as a catalytic agent, which helps in the conversion of nitrogen-containing organic compounds into ammonium sulfate.

5. **Final Answer**:
- The correct option is that CuSO4 acts as a catalytic agent in Kjeldahl's method.