0.28 g of an organic compound in Dumas method liberated 24 ml of nitrogen at STP. The percentage of nitrogen in the compound is

Options

A. 20
B. 10.71
C. 80
D. 50

Answer

To find the percentage of nitrogen in the organic compound using the Dumas method, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Mass of the organic compound = 0.28 g
- Volume of nitrogen gas (N₂) liberated at STP = 24 ml

2. **Use the Formula for Percentage of Nitrogen:**
The formula to calculate the percentage of nitrogen in the organic compound using the Dumas method is:
\[ \text{Percentage of Nitrogen} = \frac{\text{Volume of } N_2 \text{ (ml at STP)}}{8 \times \text{Weight of organic compound (g)}} \]

3. **Substitute the Values into the Formula:**
- Volume of nitrogen (N₂) = 24 ml
- Weight of the organic compound = 0.28 g

Plugging these values into the formula gives:
\[ \text{Percentage of Nitrogen} = \frac{24 \text{ ml}}{8 \times 0.28 \text{ g}} \]

4. **Calculate the Denominator:**
- First, calculate \(8 \times 0.28\):
\[ 8 \times 0.28 = 2.24 \]

5. **Complete the Calculation:**
Now, substitute back into the formula:
\[ \text{Percentage of Nitrogen} = \frac{24}{2.24} \]

6. **Final Calculation:**
- Performing the division:
\[ \text{Percentage of Nitrogen} \approx 10.71\% \]

### Conclusion:
Thus, the percentage of nitrogen in the organic compound is approximately **10.71%**.