Most of the naturally occurring processes are spontaneous.
a) Give the criteria for spontaneity of a process in terms of free energy change (`DeltaG`)
b) Exothermic reactions associated with a decrease in entropy are sponaneous at lower temperatures. Justify on the basis of Gibbs equation.
c) Find the temperature above which the reactin `MgO_((s))+C_((s))rightarrow`
`Mg_((s))+CO_((g))` becomes spontaneous.
(Given (`Delta_rH^theta=490kJmol^-1 & Delta_rS^theta=198JK mol^-1`)