question_answer

The formation of the oxide ion \[O_{(g)}^{2-}\] requires first an exothermic and then an endothermic step as shown below   \[{{O}_{(g)}}+{{e}^{-}}=O_{(g)}^{-}\Delta {{H}^{0}}=-142\ kJmo{{l}^{-1}}\] \[O_{(g)}^{-}+{{e}^{-}}=O_{(g)}^{2-}\Delta {{H}^{0}}=844\ kJmo{{l}^{-1}}\] This is because [AIEEE 2004]

A) \[{{O}^{-}}\] ion will tend to resist the addition of another electron

B) Oxygen has high electron affinity

C) Oxygen is more electronegative

D) \[{{O}^{-}}\]ion has comparatively larger size than oxygen atom