In the Duma's method for estimating nitrogen in an organic compound, the gas finally collected is

Options

A. `N_2`
B. `NO`
C. `NH_3`
D. None of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Dumas Method**: The Dumas method is a technique used to determine the nitrogen content in organic compounds. It involves the combustion of the organic sample in the presence of copper oxide.

2. **Combustion Reaction**: When the organic compound is heated with copper oxide, it undergoes oxidation. The general reaction can be represented as:
\[ \text{Organic Compound} + \text{CuO} \rightarrow \text{N}_2 + \text{CO}_2 + \text{H}_2\text{O} \]
Here, nitrogen gas (N₂), carbon dioxide (CO₂), and water (H₂O) are produced.

3. **Collection of Gases**: After the reaction, the gases produced are collected. The carbon dioxide and water vapor are absorbed using potassium hydroxide (KOH), which leaves behind nitrogen gas.

4. **Final Collection**: The only gas that remains unabsorbed and is collected is nitrogen gas (N₂).

5. **Estimation of Nitrogen**: The weight of the nitrogen gas collected is then used to calculate the percentage of nitrogen in the original organic compound.

6. **Conclusion**: Therefore, the gas finally collected in Dumas method for estimating nitrogen in an organic compound is nitrogen gas (N₂).

**Final Answer**: The correct option is **A) Nitrogen (N₂)**.

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