Question

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?

Answer 1

So how do you know? Got me.....?

Explanation:

Of course, you have to look at the context of the question.......`"Iron metal is heated under excess dioxygen gas for a "`
`"prolonged period........"` Such conditions, would favour oxidation to `"ferric iron"`.

`2Fe(s) + 3/2O_2(g) +Delta rarrFe_2O_3(s)`

On the other hand, `"iron oxalate"` can be thermally decomposed to `"iron oxide"` and `"carbon dioxide"` and `"carbon monoxide"`.

`FeC_2O_4(s)+Delta rarrFeO(s) + CO(g) + CO_2(g)`

On the other, other hand, `"ferrous oxide"` could disproportionate to give iron metal and the mixed oxidation state `"magnetite"`.....

`3FeO(s) + DeltararrFe(s) + Fe_2O_3(s)`

.........here `Fe_2O_3` `"aka magnetite"` is a mixed oxidation state iron oxide.......`FeO*FeO_2`, i.e. an `Fe(+IV)` centre........

Depending where you are, you should be spoon-fed this info.