In the early days of automobiles, illumination at night was provided by burning acetylene, C2H2….

In the early days of automobiles, illumination at night was
provided by burning acetylene, C2H2. Though no longer used as auto headlamps,
acetylene is still used as a source of light by some cave explorers. The
acetylene is (was) prepared in the lamp by the reaction of water with calcium
carbide, CaC2: CaC2 (s) + 2H2 O(l) _
Ca(OH)2 (s) + C2 H2 (g). Calculate the standard enthalpy of the reaction. The
_Hf ° of CaC2 is _15.14 kcal/mol.