The correct increasing order of bond length among the following is
O 2 + , O 2 , O 2 − , O 2 2 −
O 2 + , O 2 , O 2 2 − , O 2 −
O22−,O2−,O2,O2+
O2−,O22−,O2+,O2
More the bond order of molecule or ion less will be the bond length
O 2 2− ⇒ BO = 1 , O 2 − ⇒ BO = 1.5
O2 ⇒ BO = 2 , O 2 + ⇒ BO = 2.5