According to the Ellingham diagram, which of the following metals can reduce chromium oxide at
?
Iron
Silver
Copper
Aluminium
According to the Ellingham diagram, which depicts the thermodynamic stability of oxides at various temperatures, the metals that can reduce chromium oxide at
are those located below the chromium line.
At , Aluminium(Al) is positioned below the chromium line, indicating that it has lower free energy of formation for its oxide compared to chromium oxide at
. This means that Aluminium(Al) is thermodynamically capable of reducing chromium oxide.
On the other hand, iron (Fe), silver (Ag), and copper (Cu) are positioned above the chromium line on the Ellingham diagram. This suggests that they have higher free energies of formation for their respective oxides compared to chromium oxide. Therefore, these metals are not capable of reducing chromium oxide at that temperature.
Hence, the correct option is 4.