The standard enthalpy of for ation `(Delta_(f) H^(@))` at 298 K for methane, `C H _(4) (g)` , is `-74 . 8 KJ mol^(-1)`.The additional information required to determine the average energy for C-H bond formation would be

Options

A. Latent heat of vapourization of methane
B. The first four ionization energies of carbon and electron gain ethalpy of hydrogen
C. The dissociation energy of hydrogen molecule `H_(2)`
D. The dissociation energy of `H_(2)` and enthalpy of sublimation of carbon

Answer

D

Explanation

`C_((s))+2H_(2(g))rarr CH_(4(g)), Delta H_(f)(CH_(4))=-74.8 kJ mol^(-1)`
`C_((s))rarr C_((g)) , Delta H`
`Delta H=(B.E.)_(R )-(B.E.)_(P)`
`Delta H=[Delta H_(C(s)rarr C(g))+2xx(B.E.)_(H-H)]-4xx(B.E.)_(C-H)`