How do we represent the formation of #FeS# by the redox reaction of iron and sulfur?

1 Answer
Mar 6, 2017

Answer:

#"Oxidation is the formal loss of electrons........"#

Explanation:

And thus, when zerovalent, i.e. elemental, iron is oxidized, we represent the oxidation on these terms:

#Fe rarr Fe^(2+) + 2e^-# #(i)#

On the other hand, #"reduction is the formal gain of electrons"#. For sulfur we have:

#S +2e^(-) rarr S^(2-)# #(ii)#

We conceive that iron and sulfur undergo formal electron transfer, so we add reactions #(i)+(ii)# so that electrons do not appear in the final equation:

#Fe + S rarr FeS#

And thus in the reverse reaction, #Fe^(2+)# is REDUCED to give elemental iron.

We would cross multiply the redox equations if there were different numbers of electrons involved in the individual redox reactions.

If iron were oxidized to #Fe^(3+)#, how would you represent the redox reaction?