Given below are two statements :
Statement (I) : Experimentally determined oxygen-oxygen bond lengths in the O₃ are found to be same and the bond length is greater than that of a O=O (double bond) but less than that of a single (O-O) bond.
Statement (II) : The strong lone pair-lone pair repulsion between oxygen atoms is solely responsible for the fact that the bond length in ozone is smaller than that of a double bond (O=O) but more than that of a single bond (O-O).
In the light of the above statements, choose the correct answer from the options given below :

Solution

Chemistry ma’am · 4 steps

Ozone's equal, in-between bond lengths come from resonance, not from lone pair repulsion.

1. Check Statement I. In O₃ both O–O bonds measure about 128 pm. A typical O=O double bond is about 121 pm and an O-O single bond is about 148 pm. So the two bonds are equal and lie between double and single. Statement I is true.
2. Why they are equal. No single Lewis structure fits ozone. Two resonance structures each have one double bond and one single bond, with the double bond in a different place. The real molecule is a hybrid of the two, so each bond has a bond order of 1.5.
3. Check Statement II. Statement II gives lone pair repulsion as the sole cause, but resonance is the real reason. It also gets the order backwards: it says the bond is shorter than a double bond and longer than a single bond, which cannot both be true. Statement II is false.
4. So. Statement I is true and Statement II is false, which is option (c).

The idea to keep. When a molecule has identical bonds of in-between length, think resonance first. Bond order 1.5 means a length between a single and a double bond.

Answer from the NTA final answer key. Solution by PrepWiser.