Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Electron affinity is positive, when

AIIMS 2013

Answer 1

The change from $O^{-}$ to $O^{2-}$ is endothermic because $O^{-}$ repels the incoming electron due to its negative charge hence, it needs additional energy to accept the electron. So, the electron affinity is positive.

Hence, option (b) is correct answer.