Consider the following reactions. In which cases is product formation favoured by decreased temperature?   (1) N2(g)+O2(g)⇌2NO(g); ΔH∘=181kJ  (2) 2CO2(g)⇌2CO(g)+O2(g); ΔH∘=566kJ  (3) H2(g)+Cl2(g)⇌2HCl(g); ΔH∘=−9.4kJ  (4) H2(g)+F2(g)⇌2HF(g); ΔH∘=−541kJ