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

1 Answer
Sep 7, 2016

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


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

#1/2O_2 + 2e^(-) rarr 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:

#Na rarr Na^(+) + e^(-)# #ii#

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:


#2Na + O_2 rarr Na_2O#

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