Which one of the following contains maximum percentage of nitrogen by mass ?

Options

A. Urea
B. Ammonium cyanide
C. Ammonium carbonate
D. Ammonium nitrate

Explanation

To determine which compound contains the maximum percentage of nitrogen by mass, we will calculate the percentage of nitrogen in each of the given compounds: Urea, Ammonium Cyanide, Ammonium Bicarbonate, and Ammonium Nitrate.

### Step-by-Step Solution:

1. **Calculate the percentage of nitrogen in Urea (NH2CONH2)**:
- **Molar Mass of Urea**:
- Nitrogen (N): 2 × 14 g/mol = 28 g/mol
- Carbon (C): 1 × 12 g/mol = 12 g/mol
- Oxygen (O): 1 × 16 g/mol = 16 g/mol
- Hydrogen (H): 4 × 1 g/mol = 4 g/mol
- Total Molar Mass = 28 + 12 + 16 + 4 = 60 g/mol
- **Percentage of Nitrogen**:
\[ \text{Percentage of N} = \left(\frac{28}{60}\right) \times 100 = 46.67\% \]

2. **Calculate the percentage of nitrogen in Ammonium Cyanide (NH4CN)**:
- **Molar Mass of Ammonium Cyanide**:
- Nitrogen (N): 1 × 14 g/mol = 14 g/mol
- Carbon (C): 1 × 12 g/mol = 12 g/mol
- Hydrogen (H): 4 × 1 g/mol = 4 g/mol
- Total Molar Mass = 14 + 12 + 4 = 30 g/mol
- **Percentage of Nitrogen**:
\[ \text{Percentage of N} = \left(\frac{14}{30}\right) \times 100 = 46.67\% \]

3. **Calculate the percentage of nitrogen in Ammonium Bicarbonate (NH4)2CO3**:
- **Molar Mass of Ammonium Bicarbonate**:
- Nitrogen (N): 2 × 14 g/mol = 28 g/mol
- Carbon (C): 1 × 12 g/mol = 12 g/mol
- Oxygen (O): 3 × 16 g/mol = 48 g/mol
- Hydrogen (H): 8 × 1 g/mol = 8 g/mol
- Total Molar Mass = 28 + 12 + 48 + 8 = 96 g/mol
- **Percentage of Nitrogen**:
\[ \text{Percentage of N} = \left(\frac{28}{96}\right) \times 100 = 29.17\% \]

4. **Calculate the percentage of nitrogen in Ammonium Nitrate (NH4NO3)**:
- **Molar Mass of Ammonium Nitrate**:
- Nitrogen (N): 2 × 14 g/mol = 28 g/mol
- Oxygen (O): 3 × 16 g/mol = 48 g/mol
- Hydrogen (H): 4 × 1 g/mol = 4 g/mol
- Total Molar Mass = 28 + 48 + 4 = 80 g/mol
- **Percentage of Nitrogen**:
\[ \text{Percentage of N} = \left(\frac{28}{80}\right) \times 100 = 35\% \]

### Summary of Results:
- Urea: 46.67%
- Ammonium Cyanide: 46.67%
- Ammonium Bicarbonate: 29.17%
- Ammonium Nitrate: 35%

### Conclusion:
Both Urea and Ammonium Cyanide have the highest percentage of nitrogen by mass, which is 46.67%. However, since the question asks for the maximum percentage, we can conclude that **Urea (NH2CONH2)** and **Ammonium Cyanide (NH4CN)** both contain the maximum percentage of nitrogen.