For testing nitrogen in organic compounds, they are fused with sodium metal, extracted with water, and treated with `FeSO_4` soln. and acidified.The presence of nitrogen is indicated by a blue or green colour or precipitate . This test is not given by

Options

A. urea
B. hdrazine
C. phenylhydrazine
D. anthranilic acid

Explanation

To solve the question regarding the detection of nitrogen in organic compounds, we need to understand the process involved in the test and identify which compound does not give a positive result.

### Step-by-Step Solution:

1. **Understanding the Test**: The test for nitrogen in organic compounds involves fusing the compound with sodium metal. This process converts the nitrogen in the organic compound into sodium cyanide (NaCN).

2. **Extraction with Water**: After fusion, the mixture is extracted with water. This step allows the soluble products, including NaCN, to dissolve in water.

3. **Reaction with Ferrous Sulfate (FeSO4)**: The solution is then treated with ferrous sulfate (FeSO4) and acidified. The presence of NaOH (formed during the fusion) will react with FeSO4 to produce a green precipitate of ferrous hydroxide (Fe(OH)2).

4. **Formation of Prussian Blue**: The green precipitate of ferrous hydroxide reacts with NaCN to form sodium ferrocyanide (Na4[Fe(CN)6]). This can further react with any remaining FeSO4 to produce a blue precipitate known as Prussian blue (Fe4[Fe(CN)6]3).

5. **Identifying Compounds**: The question asks which compound does not give this test. We analyze the options:
- **Urea (NH2CONH2)**: Contains both carbon and nitrogen, will give a positive test.
- **Hydrazine (NH2NH2)**: Contains nitrogen but lacks carbon, hence will not give a positive test.
- **Phenyl Hydrazine (C6H5NHNH2)**: Contains both carbon and nitrogen, will give a positive test.
- **Anthranilic Acid (C6H4(NH2)COOH)**: Contains both carbon and nitrogen, will give a positive test.

6. **Conclusion**: The compound that does not give the test is **Hydrazine (NH2NH2)**, as it lacks carbon.

### Final Answer:
The correct answer is **B) Hydrazine (NH2NH2)**.