# How to identify which species will undergo Oxidation and which will go Reduction

I have been given $\ce{B2}$, $\ce{N2}$, $\ce{(O2)-}$ and $\ce{O2}$.

I have to short out which will undergo oxidation, reduction or both.

How can I tell it when reactants are not given?

• $\ce{B2}$ or $\ce{Br2}$? – Klaus-Dieter Warzecha Jan 7 '17 at 9:49
• @KlausWarzecha $\ce{B2}$ – user39390 Jan 7 '17 at 10:09

You have to look at the possible oxidation states of the atoms involved. For instance, if you were given the molecule $\ce{F2}$, you should consider that fluorine has two possible oxidation states: 0 (in the $\ce{F2}$ molecule) and -1. Hence, $\ce{F2}$ can only undergo reduction. For the other molecules, you should use the same strategy: try yourself!