Q 1 :    

Which of the following processes does not involve oxidation of iron?             [2015]

• Formation of $\mathrm{Fe}{\left(\mathrm{CO}\right)}_{₅}$ from Fe.

   

• Liberation of ${\mathrm{H}}_2$ from steam by iron at high temperature.

   

• Rusting of iron sheets.

   

• Decolourisation of blue ${\mathrm{CuSO}}_4$ solution by iron.