Given below are two statements : Statement (I) : The correct sequence of bond lengths in the following species is : $\mathrm{O}_{2}^{+} \mathrm{O}_{2}^{+}>\mathrm{O}_{2}^{-}>\mathrm{O}_{2}^{2-}$ In the light of the above statements, choose the correct answer from the options given below :

(C) Statement I is true but Statement II is false

(A) Both Statement I and Statement II are true

(B) Both Statement I and Statement II are false

(D) Statement I is false but Statement II is true

JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Chemical Bonding and Molecular Structure

Given below are two statements :

Statement (I) : The correct sequence of bond lengths in the following species is :

O_{2}^{+} < O_{2} < O_{2}^{-} < O_{2}^{2 -}

Statement (II) : The correct sequence of number of unpaired electrons in the following species is :

O_{2} > O_{2}^{+} > O_{2}^{-} > O_{2}^{2 -}

In the light of the above statements, choose the correct answer from the options given below :

Answer: (C)

From molecular-orbital filling the bond orders are

O_{2}^{+} 2.5

O_{2} 2.0

O_{2}^{-} 1.5

and

O_{2}^{2 -} 1.0

; since bond length increases as bond order falls, the order

O_{2}^{+} < O_{2} < O_{2}^{-} < O_{2}^{2 -}

is correct. The numbers of unpaired electrons are

O_{2}^{+} 1

O_{2} 2

O_{2}^{-} 1

and

O_{2}^{2 -} 0

, so

O_{2}^{+}

and

O_{2}^{-}

have the same count and the strict order

O_{2} > O_{2}^{+} > O_{2}^{-} > O_{2}^{2 -}

does not hold. The first statement is true and the second is false.

JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Single correct option