Which of the following molecules has the shortest nitrogen-nitrogen bond?

• A. N_2H_2
• B. N_2H_4
• C. N_2
• D. NO_2

Answer: (C)

Verified step by step guidance

1. Step 1: Understand that the length of a bond between two atoms depends on the bond order; higher bond order corresponds to shorter and stronger bonds.
2. Step 2: Identify the nitrogen-nitrogen bonds in each molecule and determine their bond orders. For example, in N_2 (nitrogen gas), the bond is a triple bond with bond order 3.
3. Step 3: For N_2H_2 (diazene), analyze the bonding: it has a double bond between the two nitrogen atoms, so bond order is 2.
4. Step 4: For N_2H_4 (hydrazine), the nitrogen-nitrogen bond is a single bond, so bond order is 1.
5. Step 5: For NO_2, note that it contains nitrogen-oxygen bonds but no nitrogen-nitrogen bond, so it is not relevant for comparing nitrogen-nitrogen bond lengths.