The heat of combustion of acetylene is `312kcal`. If heat of formation of `CO_(2)` and `H_(2)O` are `94.38` and `68.38 kcal` respectively. Calculate `C-=C` bond energy. Given that heat of atomisation of `C` and `H` are `150.0` and `51.5kcal` respectively and `C-H` bond energy is `93.64kcal`.