Q.16. The bond length O-O in dioxygen (i.e. $O_2$) molecule is 120 pm. What would be the expected O- O bond length in $O_2\left[As{F}_4\right]$?
(A) 120 pm
(B) 112 pm
(C) 128 pm
(D) 149 pm

Dear student,
The compound O₂AsF₄ has O₂⁺ and [AsF₄]^- ion.
In formation of O₂⁺ an electron is removed from antibonding molecular orbital thereby increasing its bond order, which results in decrease of bond length.

Hence the answer is B

Hope it helps
Regards