The heat of formation of `CO and CO_(2)` are `-26.4kCal and -94 kCal ` , respectively. Heat of combustion of carbon monoxide will be

Explanation

`C+1//2O_2 to CO " " DeltaH`=-26.4 K.cal …(1)
`C+O_2 to CO_2 " " DeltaH`=-94 K.cal …(2)
Heat of combustion of CO is `C+1//2O_2 to CO_2 " " DeltaH`= ?
Equation (1) is reversed .
`{:(CO to cancelC+1/cancel2O_2 " " DeltaH="+26.4 K.cal"),(cancelC+cancelO_2to CO_2 " " DeltaH="-94 K.cal" " ""[Add equation (2)]"):}/(C_((g))+1//2O_(2(g)) to CO_(2(g))" "DeltaH="-94 +26.4")`
`DeltaH`=-67.6 K.cal