Question

The correct order of the $O - O$ bond length in $O_2,H_2 O_2 $ and $O_3 $ is

• A. $O_2 > O_3 > H_2O_2$
• B. $O_3 > H_2O_2 > O_2 $
• C. $O_2 > H_2O_2 >O_3$
• D. $H_2O_2 > O_3 > O_2 $

Answer 1

The Correct Option is D

To determine the correct order of the O - O bond length in O_2, H_2 O_2, and O_3, we need to consider the type of bonding and molecular structure present in each molecule.

1. Oxygen molecule (O_2):
   • The O_2 molecule consists of two oxygen atoms connected by a double bond.
   • The double bond consists of one sigma bond and one pi bond.
   • The bond length in a double bond is typically shorter than a single bond due to greater overlap of orbitals.
   • Therefore, O_2 has a relatively short bond length.
2. Hydrogen peroxide (H_2 O_2):
   • H_2 O_2 has two oxygen atoms connected by a single bond.
   • Single bonds generally have a longer bond length compared to double bonds.
   • Therefore, the O - O bond length in H_2 O_2 is longer than that in O_2.
3. Ozone (O_3):
   • Ozone consists of three oxygen atoms and is a resonance hybrid of two main structures.
   • It has partial double bond character due to resonance, leading to a bond length that is intermediate between a single and a double bond.
   • Therefore, the bond length in O_3 is longer than that in O_2, but shorter than that in H_2 O_2.

Based on this analysis, the order of increasing O - O bond length is:

H_2O_2 > O_3 > O_2

This is because H_2O_2 has the longest bond length (single bond), followed by O_3 (partial double bond character), and then O_2 (double bond) having the shortest bond length.