Given : `S_((s))+(3)/(2)O_(2(g))rarrSO_(3(g)+2X Kcal`
`SO_(2(s))+(1)/(2)O_(2(g))rarrSO_(3(g)+Y Kcal`
The heat of formation of `SO_(2)` is `:-`

Options

A. `(x+y)`
B. `(x-y)`
C. `(2x+y)`
D. `(2x-y)`

Answer

D

Explanation

`S(s) + (3)/(2)O_(2)(g) to SO_(3) (g) + 2x` Kcal …(i)
By inverting second equation we get,
`SO_(3)(g) to SO_(2)(g) + (1)/(2)O_(2)(g) -y` kcal …(ii)
On addition Eqs. (i) and (ii)
`S(s) + O_(2)(g) to SO_(2)(g) + (2x-y)` kcal
Hence , heat of formation of `SO_(2)` is (2x-y) kcal