In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia avolved from 0.75 g of sample neutralized 10 mL of 1 M `H_(2)SO_(4)`. The percentage of nitrogen in the soil is

Options

A. 35.33
B. 43.33
C. 37.33
D. 45.33

Explanation

To find the percentage of nitrogen in the soil sample using Kjeldahl's method, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Mass of the soil sample = 0.75 g
- Volume of H₂SO₄ used = 10 mL
- Molarity of H₂SO₄ = 1 M

2. **Convert Molarity to Normality:**
- The normality (N) of H₂SO₄ can be calculated using the formula:
\[ \text{Normality} = \text{Molarity} \times n \]
- For H₂SO₄, which can donate 2 protons (H⁺ ions), the n-factor is 2.
- Therefore, the normality of H₂SO₄ is:
\[ \text{Normality} = 1 \, \text{M} \times 2 = 2 \, \text{N} \]

3. **Use the Formula for Percentage of Nitrogen:**
- The formula for calculating the percentage of nitrogen (N) in the soil sample is:
\[ \text{Percentage of Nitrogen} = \frac{1.4 \times \text{Normality} \times \text{Volume of H₂SO₄}}{\text{Mass of sample}} \]
- Substitute the values:
\[ \text{Percentage of Nitrogen} = \frac{1.4 \times 2 \, \text{N} \times 10 \, \text{mL}}{0.75 \, \text{g}} \]

4. **Calculate the Percentage of Nitrogen:**
- First, calculate the numerator:
\[ 1.4 \times 2 \times 10 = 28 \]
- Now, divide by the mass of the sample:
\[ \text{Percentage of Nitrogen} = \frac{28}{0.75} \approx 37.33\% \]

5. **Final Result:**
- The percentage of nitrogen in the soil sample is approximately **37.33%**.