下列热化学方程式书写正确的是                      

A．2SO2+O22SO3； △H=-196.6kJ/mol

B．C(s)+O2(g)==CO2(g)；△H=393.5kJ/mol

C．1/2H2(g)+1/2Cl2(g)==HCl(g)；△H=-92.5kJ/mol

D．H^+(aq)+OH^-(aq)==H2O(l)；△H=57.3kJ