Calcaulte reaction enthalpy of the following reaction at `25^(@)C`.
`SO_(2)(g)+2H_(2)S(g) to 3S("rhombic")+2H_(2)O(l)`.
Given : `DeltaH_(f)^(0) " of " SO_(2)(g), H_(2)S(g)`, S (rhombic) and `H_(2)O(l) " at " 25^(@)C " are " -70.96, -4.82, 0 and -68.32 " kcal mol"^(-1)` respectively.

Explanation

`S("rhombic")+O_(2)(g) to SO_(2)(g)`,
`Delta H^(0)= - 70.96 " kcal mol"^(-1)`
S(rhombic)`+H_(2)(g) to H_(2)S(g)`,
`Delta H^(0)= - 4.82 " kcal mol"^(-1)`
`H_(2)(g)+(1)/(2)O_(2)(g) to 2H_(2)O(l)`,
`Delta H^(0)= -68.32 " kcal mol"^(-1)`
`2xx "equation " [3] -2 xx " equation " [2] -"equation"[1]`, we have `SO_(2)(g)+2H_(2)S(g) to 3S("rhombic")+2H_(2)O(l)`
`Delta H^(0)= [2-(-68.32)-2(-4.82)-(-70.96)]` kcal
`=-56.04` kcal