How do you know how to...?
#(i)# represent the complete oxidation of iron metal to ferric oxide?
#(ii)# represent the thermal decomposition of ferrous oxalate?
#(iii)# represent the disproportionation of ferrous oxide?
So how do you know? Got me.....?
Of course, you have to look at the context of the question.......
On the other hand,
On the other, other hand,
Depending where you are, you should be spoon-fed this info.