S1: Ellingham diagram is used to check which metal oxide is to be reduced by which compound.
S2: In Ellingham diagram as we move from left to right, ∆S always increases.
(a) Both S1 and S2 are correct.
(b) S1 is correct but S2 is incorrect.
(c) S1 is incorrect but S2 is correct.
(d) Both S1 and S2 are incorrect.
Correct answer: (b) S1 is correct but S2 is incorrect.
Explanation:
∆H (enthalpy change) and the ∆S (entropy change) values for any chemical reaction remain nearly constant even on varying temperature. So the only dominant variable becomes T. However. ∆S depends much on the physical state of the compound. Since entropy depends on disorder or randomness in the system. It will increase if a compound melt (s → l) or vaporises (l → g) since molecular randomness increases on changing the phase from solid to liquid or from liquid to gas.