Which of the following processes does not involve oxidation of iron ?

Options

A. formation of `Fe(CO)_(5)` from Fe
B. Liberation of `H_(2)` from steam by iron at high temprature
C. rusting of iron sheets
D. decolourisation of blue `CuSO_(4)` solution by iron

Answer

a

Explanation

(a) oxidation does not occur during formation of `Fe(CO)_(5)` from Fe since O.N of iron remains to be zero
`overset(0)Fe+5cOrarroverset(0)Fe(CO)_(5)`
In all other cases oxidation of Fe occurs since its O.N increases
(b) `3Fe(s)+4H_(2)O(g)rarrFe_(3)O_(4)(s)+4H_(2)(g)`
(c )`4Fe+3O_(2)+xH_(2)Orarr2Fe_(2)O_(3)xH_(2)O`
(d) `CuSO_(4)+FerarrFeSO_(4)+cu`