Calculate the enthalpy of formation of aniline. The enthalpy of combustion of aniline is `837.5 kcal mol^(-1)`. The enthalpies of formation of liquid water and gaseous carbon dioxide are `-68.4` and `-97.0kcal mol^(-1)` respectively. All values are at `298 K`.

Explanation

`6C(s) +(7)/(2)H_(2)(s) +(1)/(2)N_(2)(s) rarr C_(6)H_(5)NH_(2)(l) Delta_(f)H = ?`
`C_(6)H_(5)NH_(2)(l) +(31)/(4)O_(2)(g) rarr 6CO_(2)(g)+(7)/(2)H_(2)O(1) +(1)/(2)N_(2) DeltaH_(f) = - 837.5 (-ve` sign combustion)
`C(s) +O_(2) (g) rarr CO_(2)(g), DeltaH_(2) =- 97.0`
`H_(2)(g) +(1)/(2)O_(2)(g) rarr H_(2)O(l), DeltaH_(3) = -68.4`
`DeltaH_(f) = 6xx(-97) +(7)/(2) (-68.4) -(837.5)`
`= 16.1 kcal mol^(-1)`