The percentage of nitrogen in a compound is determined by

Options

A. Dumas method
B. Kjeldahl's method
C. Carius method
D. substraction the sum of percentages of all other elements present from `100`.

Answer

To determine the percentage of nitrogen in a compound, we can use two methods based on the information provided:

### Step-by-Step Solution:

1. **Identify the Methods**:
- The question provides four options for determining the percentage of nitrogen in a compound:
1. Biomass method
2. Jaldal method
3. KDS method
4. Subtraction of the sum of the percentage of all other elements from 100.

2. **Evaluate the Jaldal Method**:
- The Jaldal method is specifically used for determining the nitrogen content in a sample. This method involves using a formula:
\[ \text{Percentage of } N = \frac{1.4 \times V \times N}{W} \]
where:
- \( V \) = volume of the solution
- \( N \) = normality of the solution
- \( W \) = weight of the sample

3. **Evaluate the Subtraction Method**:
- The second method involves calculating the percentage of nitrogen by subtracting the sum of the percentages of all other elements from 100. This can be expressed as:
\[ \text{Percentage of } N = 100 - (\text{Percentage of other elements}) \]
- This method is valid if the total percentage of all elements in the compound sums up to 100%.

4. **Conclusion**:
- Based on the evaluation, both the Jaldal method and the subtraction method are valid for determining the percentage of nitrogen in a compound. Therefore, the correct answers are:
- Option 2: Jaldal method
- Option 4: Subtraction of the sum of the percentage of all other elements from 100.

### Final Answer:
The percentage of nitrogen in a compound is determined by:
- Option 2: Jaldal method
- Option 4: Subtraction of the sum of the percentage of all other elements from 100.