Question

what is the oxidation number of the nitrogen atom (N) in NH3 and in HNO3

Answer 1

To determine the oxidation number of nitrogen in both compounds, we can follow these guidelines:

1. **In ammonia (NH₃)**:
- The oxidation number of hydrogen (H) is +1.
- Let the oxidation number of nitrogen (N) be \( x \).
- The overall charge of the molecule is neutral (0).
- The equation can be set up as follows:
\[
x + 3(+1) = 0
\]
Simplifying this gives:
\[
x + 3 = 0 \\
x = -3
\]
- Therefore, the oxidation number of nitrogen in NH₃ is **-3**.

2. **In nitric acid (HNO₃)**:
- The oxidation number of hydrogen (H) is +1, and the oxidation number of oxygen (O) is usually -2.
- Let the oxidation number of nitrogen (N) be \( x \).
- The overall charge of the molecule is neutral (0).
- The equation can be set up as follows:
\[
+1 + x + 3(-2) = 0
\]
Simplifying this gives:
\[
+1 + x - 6 = 0 \\
x - 5 = 0 \\
x = +5
\]
- Therefore, the oxidation number of nitrogen in HNO₃ is **+5**.

In summary:
- The oxidation number of nitrogen in NH₃ is **-3**.
- The oxidation number of nitrogen in HNO₃ is **+5**.