N2(g)+ H2(g)=NH3(g)△H=﹣46.19kJ•mol﹣1
H2(g)+ Cl2(g)=HCl(g)△H=﹣92.36kJ•mol﹣1
I2(g)+ H2(g)=HI(g)△H=﹣4.74kJ•mol﹣1 .