\(\rm{HCN}\)无色有杏仁气味的有毒气体,早期广泛用于船舱、仓库的烟熏灭鼠\(\rm{.}\)已知:\(\rm{HCN(}\) \(\rm{aq)}\)与\(\rm{NaOH(aq)}\)反应的焓变\(\rm{\triangle H=-12.1kJ⋅mol^{-1}}\); \(\rm{HCl(aq)}\)与\(\rm{NaOH(aq)}\)反应的焓变\(\rm{\triangle H=-55.6kJ⋅mol^{-1}.}\)则\(\rm{HCN}\)在水溶液中电离的焓变\(\rm{\triangle H}\)等于\(\rm{(}\) \(\rm{)}\)