Question

the bond dissociation energy of H2 CL2 and HCl are 104, 58, 103 kcal respectively. the enthalpy of formation of HCL gas will be
-44kcal -88kcal -22kcal -11kcal

Answer 1

First you need to write a balanced equation:
\[H_2+Cl_2=>2HCl\]
\[\Delta H=Bonds broken - Bonds formed \]
\[\Delta H=104kcal+58kcal-2(103kcal)\]
\[\Delta H=162kcal-206kcal\]
\[\Delta H=-44kcal\]