Explain the following observation :
In the structure of `HNO_(3)` the N-O bond (121 pm) is shorter than the N-OH bond (140 pm).

Explanation

To explain the observation that the N-O bond in HNO₃ (121 pm) is shorter than the N-OH bond (140 pm), we can analyze the structure and bonding characteristics of nitric acid.

### Step-by-Step Solution:

1. **Understanding the Structure of HNO₃**:
- HNO₃, or nitric acid, has a molecular structure that includes nitrogen (N) bonded to three oxygen (O) atoms. Among these, one oxygen is bonded to a hydrogen atom (OH group), while the other two are involved in double bonds with nitrogen.

2. **Resonance Structures**:
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