Short Answer Type
Long Answer TypeShort Answer TypeA compound has more thermodynamic stability if the ionization energy of the metal is low. Since the ionization energy of Ni2+ is less than that for Pt2+, therefore Ni2+, compounds are thermodynamically more stable than Pt2+ compounds.
Ni → Ni2+ + 2e– ΔH = 2490 kJ mol–1
(low energy more stable)
Pt → Pt2+ + 2e– ΔH = 2660 kJ mol–1
(high energy less stable)
Pt4+ compounds are stable than Ni4+ compounds because the energy needed to remove 4 electrons in Pt is less than that in Ni.
Pt → pt4+ + 4e– ΔH = 6770 kJ mol–1
(low energy more stable)
Ni → Ni4+ + 4e– ΔH = 8800 kJ mol–1
(high energy, less stable)
Account for the following facts:
The reduction of a metal oxide is easier if the metal formed is in liquid state at the temperature of reduction.
Account for the following facts:
The reduction of Cr2O3 with Al is the thermo-dynamically feasible, yet it does not occur at room temperature.
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