# What part of a reaction involves oxidation or reduction, but not both?

Jul 20, 2016

Half equations, which we use to solve redox reactions.

#### Explanation:

Consider the reduction of intensely purple $M n {O}_{4}^{-}$ to give colourless $M {n}^{2 +}$:

$M n {O}_{4}^{-} + 8 {H}^{+} + 5 {e}^{-} \rightarrow M {n}^{2 +} + 4 {H}_{2} O$

As written, this is a reduction reaction, the which includes electrons, which are conceived to reduce the manganese centre. The reduction reaction must be accompanied by a corresponding oxidation reaction to supply the electrons.

I acknowledge that the use of electrons is a little bit abstract; but their use indicates electron transfer, which characterizes redox behaviour and allows us to balance such equations.