The heat of combustion of acetylene is 312 Kcal . If heat of formation of `CO_(2) & H_(2)O` are -94 & -68 Kcal respectively . Given that heat of atomisation of C& H are 150 & 50 Kcal respectively and C-H bond energy is 93 Kcal . Calculate `(DeltaH_(C=C))/(6)`

Answer

9

Explanation

`H-C -= C-H + (5)/(2)O_(2) rarr 2CO_(2) + H_(2)O, " " -312` Kcal.
`-312 = 2x (-94) + (-68) -DeltaH_(f(C_(2)H_(2)).`
`DeltaH_(f(C_(2)H_(2)))=56` Kcal .

`56 = 2 xx 150 + 50 -2 xx 93 -2x.`
`x=54` Kcal
`(DeltaH_(C=C))/(6) = (X)/(6) = 9`