In which of the following compounds , the nitrogen atom exhibits negative oxidation state?

Options

A. Sodium nitrate
B. NO
C. Sodium azide
D. Sodium nitrite

Answer

To determine in which of the following compounds the nitrogen atom exhibits a negative oxidation state, we will analyze each compound one by one.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds we need to analyze are:
- Sodium Nitrate (NaNO3)
- Nitric Oxide (NO)
- Sodium Azide (NaN3)
- Sodium Nitrite (NaNO2)

2. **Analyze Sodium Nitrate (NaNO3)**:
- Sodium (Na) has an oxidation state of +1.
- Oxygen (O) typically has an oxidation state of -2. There are 3 oxygen atoms, contributing a total of -6.
- Let the oxidation state of nitrogen (N) be \( x \).
- The overall charge of the compound is 0, so we set up the equation:
\[ +1 + x + (-6) = 0 \]
\[ x - 5 = 0 \implies x = +5 \]
- **Conclusion**: Nitrogen in NaNO3 is in the +5 oxidation state.

3. **Analyze Nitric Oxide (NO)**:
- Oxygen (O) has an oxidation state of -2.
- Let the oxidation state of nitrogen (N) be \( x \).
- The overall charge of the compound is 0, so we set up the equation:
\[ x + (-2) = 0 \]
\[ x - 2 = 0 \implies x = +2 \]
- **Conclusion**: Nitrogen in NO is in the +2 oxidation state.

4. **Analyze Sodium Azide (NaN3)**:
- Sodium (Na) has an oxidation state of +1.
- Let the oxidation state of nitrogen (N) be \( x \) for each nitrogen atom.
- There are 3 nitrogen atoms, so the equation becomes:
\[ +1 + 3x = 0 \]
\[ 3x = -1 \implies x = -\frac{1}{3} \]
- **Conclusion**: Each nitrogen in NaN3 has an oxidation state of -1/3. This indicates that nitrogen exhibits a negative oxidation state.

5. **Analyze Sodium Nitrite (NaNO2)**:
- Sodium (Na) has an oxidation state of +1.
- Oxygen (O) has an oxidation state of -2. There are 2 oxygen atoms, contributing a total of -4.
- Let the oxidation state of nitrogen (N) be \( x \).
- The overall charge of the compound is 0, so we set up the equation:
\[ +1 + x + (-4) = 0 \]
\[ x - 3 = 0 \implies x = +3 \]
- **Conclusion**: Nitrogen in NaNO2 is in the +3 oxidation state.

### Final Conclusion:
The only compound where nitrogen exhibits a negative oxidation state is **Sodium Azide (NaN3)**.