Chemical Bonding and Molecular Structure — JEE Main · 2025 · 24 Jan 2025 · Shift 2 Question with Solution

Given below are two statements :

Statement(I) : Experimentally determined oxygen-oxygen bond lengths in the

O_{3}

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:

(A)Statement I is true but Statement II is false✓ Correct
(B)Both Statement I and Statement II are true
(C)Both Statement I and Statement II are false
(D)Statement I is false but Statement II is true

Answer: (A)

Solution

Ozone's two O–O bonds are experimentally identical in length and lie between a pure

O = O

double bond and a pure

O - O

single bond — exactly what resonance predicts. Ozone is a hybrid of two equivalent structures,

O = O^{+} - O^{-} \leftrightarrow^{-} O - O^{+} = O

, giving each bond a bond order of 1.5 and equalizing the two bond lengths. Statement I, describing this observed intermediate and equal bond length, is correct.

Statement II attributes this intermediate length solely to lone pair–lone pair repulsion between the terminal oxygens. Lone-pair repulsion does compress the bond angle below the ideal

12 0^{\circ}

, but the intermediate bond length itself comes from resonance delocalization of the

π

electrons over both O–O bonds, not from lone-pair repulsion. Statement II is false.

JEE Main · 2025 · 24 Jan 2025 · Shift 2 · Single correct option

JEE Main · 2025 · 24 Jan 2025 · Shift 2 · Chemical Bonding and Molecular Structure

Solution

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