Hydrazine does not give Lassaigne's test for nitrogen. Why ?

Explanation

### Step-by-Step Solution:

1. **Understanding Lassaigne's Test**: Lassaigne's test is a qualitative analysis method used to detect the presence of nitrogen in organic compounds. The test involves fusing the organic compound with sodium metal, which helps in forming sodium cyanide (NaCN) if nitrogen is present in the compound.

2. **Structure of Hydrazine**: The molecular formula of hydrazine is N2H4, which can be represented structurally as NH2-NH2. It consists solely of nitrogen and hydrogen atoms, with no carbon atoms present.

3. **Requirement for Lassaigne's Test**: For Lassaigne's test to be positive for nitrogen, the organic compound must contain carbon. This is because sodium reacts with carbon in the presence of nitrogen to form sodium cyanide (NaCN), which is a necessary component for the subsequent tests to confirm the presence of nitrogen.

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