Overall: #2xx(i) + 3xx(ii)#
#2Fe_2O_3 + 3C(s) rarr 4Fe(s) + 3CO_2(g)#
These are balanced with respect to (i) mass, and (ii) charge, as in fact it must be!
Clearly I have been able to cancel the waters and #H^+#. Charge is balanced; mass is balanced. This represents a reasonable reaction for iron smelting. Industrially, coke is heated to give (red-hot!) carbon monoxide, which is injected (blasted!) into the iron oxide slag, where it performs the redox reaction. Note that I do not utilize dioxygen gas in these equations, because I want to represent the redox behaviour of iron and carbon only, so I need separate redox couples.
