已知：HCN(aq)与NaOH(aq)反应的△H=-12.1kJ·mol^-1；HCl(aq)与NaOH(aq)反应的△H=-55.6kJ·mol^-1。则HCN在水溶液中电离的△H等于（    ）                                                                     

A．-67.7 kJ·mol^-1                           B．-43.5 kJ·mol^-1             C．+43.5 kJ·mol^-1            D．+67.7 kJ·mol^-1

已知：HCN(aq)与NaOH(aq)反应的△H=-12.1kJ·mol^-1；HCl(aq)与NaOH(aq)反应的△H=-55.6kJ·mol^-1。则HCN在水溶液中电离的△H等于（    ）                                                                     

A．-67.7kJ·mol^-1                           B．-43.5 kJ·mol^-1             C．+43.5 kJ·mol^-1            D．+67.7 kJ·mol^-1

已知：HCN(aq)与NaOH(aq)反应的ΔH＝-12.1 kJ·mol^-1；HCl(aq)与NaOH反应的ΔH＝-12.1 kJ·mol^-1，则HCN在水溶液中电离的ΔH等于

1. A.
   -67.7 kJ·mol^-1
2. B.
   -43.5 kJ·mol^-1
3. C.
   +43.5 kJ·mol^-1
4. D.
   +67.7 kJ·mol^-1

已知：HCN(aq)与NaOH(aq)反应的ΔH＝－12.1 kJ·mol^－1；HCl(aq)与NaOH(aq)反应的ΔH＝－57.3 kJ·mol^－1，则HCN在水溶液中电离的ΔH等于