# Redox refers to a substance gaining an electron and releasing what?

Sep 7, 2016

Redox chemistry relates to electron transfer: the formal loss or gain of electrons.

#### Explanation:

A substance that accepts electrons is an oxidant, an oxidizing agent:

$\frac{1}{2} {O}_{2} + 2 {e}^{-} \rightarrow {O}^{2 -}$ $i .$

In accepting the electrons it has in fact been reduced.

A substance that donates electrons is an reductant, a reducing agent, and in losing those electrons it is itself manifestly oxidized:

$N a \rightarrow N {a}^{+} + {e}^{-}$ $i i$

We include electrons in these half equations, as a means to help balance with respect to charge. We add the half equation together to remove the electrons from the final redox equation:

$\left(i\right) + 2 \times \left(i i\right)$

$2 N a + {O}_{2} \rightarrow N {a}_{2} O$

In all instances, charge must be balanced as well as mass.