Standard enthalpy of combustion of `CH_(4)(g) " is " 802.8 " kJ mol"^(-1)`. If the bond dissociation energies of `C-H, O=O and O-H` bonds are 416.2, 493.7 and `464.4 " kJ mol"^(-1)` respectively then calculate the bond dissociation energy of C=O bond.

Explanation

`CH_(4)(g)+2O_(2)(g) to CO_(2)(g)+2H_(2)O(l) , Delta H^(0)= -802.8 " kJ mol"^(-1)`
`Delta H^(0)= [4 xx " bond energy of " C- H + 2xx " bond energy of " O= O]`
` -[(2xx " bond energy of " C=O+4 xx " bond energy of " O-H]`
or, `-802.8=(4xx416.2+2xx493.7)-(2xx " bond energy of " C= O +4xx464.4)`
`therefore` Bond energy of `C= O = 798.7 " kJ mol"^(-1)`