Class 11 NEET Chemistry Chemical Thermodynamics

The sign and magnitude of Gibbs free energy is a criterion of spontaneity for a process. When ∆G>0 or +ve, it means G‌product ‌>G‌reactant ‌
the reaction will not take place spontaneously,i.e. the reaction should be spontaneous in reverse direction.
SnO2→SnO;‌‌∆G>0
+4  +2
(more favourable )
∆G<0 or -ve, the reaction or change occurs spontaneously.
PbO2→PbO;→∆G<0
+4   +2
    (more favourable)