In Which of the following molecule would you expect the introgen to nitrogen bond to be longest ?

Options

A. `N_(2)O`
B. `N_(2)O_(4)`
C. `N_(2)H_(4)`
D. `N_(2)`

Explanation

To determine which nitrogen to nitrogen (N-N) bond is the longest among the given molecules, we need to analyze the types of bonds present in each molecule. The bond length is influenced by the bond order, which is the number of shared electron pairs between two atoms. Generally, the bond lengths follow this trend:

1. **Single bond (longest)**
2. **Double bond (intermediate)**
3. **Triple bond (shortest)**

### Step-by-Step Solution:

1. **Identify the Molecules:**
We need to consider the nitrogen-containing molecules given in the question. Let's denote them as:
- Option 1: N₂O
- Option 2: N₂O₄
- Option 3: N₂H₄
- Option 4: N₂ (which has a triple bond between the nitrogen atoms)

2. **Determine Bond Types:**
- **N₂O:** Contains a triple bond between the two nitrogen atoms in its most stable form, which would make the N-N bond relatively short.
- **N₂O₄:** Contains a double bond between nitrogen atoms in some resonance structures, which would also result in a shorter bond length than a single bond.
- **N₂H₄:** Contains a single bond between the nitrogen atoms. This bond will be longer than both double and triple bonds.
- **N₂:** Contains a triple bond, which is the shortest bond type.

3. **Compare the Bond Lengths:**
- The N-N bond in N₂O (triple bond) is the shortest.
- The N-N bond in N₂O₄ (double bond) is shorter than a single bond but longer than a triple bond.
- The N-N bond in N₂H₄ (single bond) is the longest among these options.
- The N-N bond in N₂ (triple bond) is also short.

4. **Conclusion:**
Since the N-N bond in N₂H₄ is a single bond, it is expected to be the longest bond among the options provided. Therefore, the answer is **N₂H₄**.

### Final Answer:
The nitrogen to nitrogen bond is longest in **N₂H₄**.