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. `-Y-X`
B. `Y-X`
C. `X+Y`
D. X -Y`

Answer

B

Explanation

`C(s) + O_(2) (g) to CO_(2) (g), Delta H_(1) = - x` …(i)
`CO (g) + (1)/(2) O_(2) (g) to CO_(2) (g), Delta H_(2) = - y` ….(ii)
For the formation of CO subtract Eqs. (ii) from (i) i.e.
`C(s) + O_(2) (g) to CO_(2) (g)`
`underline(underset((-))(CO(g) + (1)/(2) underset((-))(O_(2) (g)) to underset((-))(CO_(2)(g)))`
`underline(C(s) + (1)/(2) O_(2) (g) to CO (g))`
`:. Delta_(r ) H` for formation of `CO = Delta H_(1) - Delta H_(2)`
= - x + y or y - x