\(\Delta H = (B.E.)_{Reactant} - (B.E.)_{product}\)
\(- 182 = (B.E.)_{H - H} + (B.E.)_{Cl - Cl} - 2(B.E.)_{H - Cl}\)
\(- 182 = 430 + 242 - 2 × (B.E.)_{H - Cl} (B.E.)_{H - Cl} = 427\, kJ \,mole^{-1}\)
${H_2}{O_{(l)}} \to \,\,H_{(aq)}^ + + \,\,OH_{(aq)}^ - \,;\,\,\,\Delta H\,\, = \,\,57.32\,\,KJ\,;$
${H_2}_{(g)} + \,\,\frac{1}{2}\,\,{O_2}_{(g)} \to \,\,{H_2}{O_{(1)}}\,;\,\,\Delta H\,\, = \,\, - 286.20\,\,KJ$