If `C(s)+O_(2)(g)to CO_(2)(g),DeltaH=rand CO(g)+1/2O_(2)to CO_(2)(g),DeltaH=s` then, the heat of formation of CO is

Options

A. `r+s`
B. `r-s`
C. `s-r`
D. rs

Answer

B

Explanation

`C(s)+O_(2)(g) to CO_(2)(g), Delta H=r " "....(i)`
`CO(g)+(1)/(2)O_(2)(g) to CO_(2) (g) , Delta H=s " "....(ii)`
`C(s)+(1)/(2)O(g) top CO(g), Delta H=?`
Substract Eq. (ii) from Eq, (i) `C(s)+O_(2)(g) to CO_(2) (g) : Delta H=r`
`CO_(g)+(1)/(g)O(g) to CO_(2)(g) , Delta H=s`
`({:(-,-,-,-):})/(underline(C(s)+(1)/(2)O_(2)(g) to CO(g), Delta H=r-s))`