∆f0S of H2O(l), NH3(g) and NO(g) respectively are –237, –108 and +104 K.Cal.mole–1. Then ∆f0S for 4NH3(g) + 5O2→ 4NO(g) + 6H2O (in K.Cal) will be
4NH3(g) + 5O2→ 4NO(g) + 6H2O , ∆f0S=?