Some reaction and their `DeltaH^(0)` values are given below:
C(graphite, s)`+(1)/(2)O_(2)(g)toCO(g),DeltaH^(0)=a` kJ
`CO(g)+(1)/(2)O_(2)(g)toCO_(2)(g),DeltaH^(0)=b` kJ
`H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l),DeltaH^(0)=c` kJ
`CH_(4)(g)+2O_(2)(g)toCO_(2)(g)+2H_(2)O(l),DeltaH^(0)=d` kJ
2C(gaphite, s)`+3H_(2)(g)toC_(2)H_(6)(g),DeltaH^(0)=m` kJ
Which of the following statements are correct-

Options

A. standard heat of formation of `CH_(4)(g)=(a+b+2c-d)kJ*mol^(-1)`
B. standard heat of combustion of `C_(2)H_(6)=(2a+2b+3c-m)kJ*mol^(-1)`
C. standard heat of combustion of carbon`=akJ*mol^(-1)`
D. standard heat of formation of `CO_(2)(g)=(a+b)kJ*mol^(-1)`.

Answer

A, B, D