以下自发反应可用ΔH判据来解释的是

A．2H2(g)+O2(g)====2H2O(l)ΔH="-285.8" kJ·mol^-

B．2N2O5(g)====4NO2(g)+O2(g)ΔH="+56.7" kJ·mol^-1

C．(NH4)2CO3(s)====NH4HCO3(s)+NH3(g)ΔH="+74.9" kJ·mol^-1

D．硝酸铵自发地溶于水