Calculate the enthalpy of formation of sulphuric acid (l) from the following data : (i) S(s)+O_(2)(g) to SO_(2)(g),DeltaH=-71.0"kcal" (ii) SO_(2)(g)+(1)/(2)O_(2)(g) to SO_(3)(g),DeltaH=-23.5"kcal" (iii) SO_(3)(g)+H_(2)O(l) to H_(2)SO_(4)(l), DeltaH=-31.2 "kcal" (iv) H_(2)(g)+(1)/(2)O_(2)(g) to H_(2)O(l),DeltaH=-68.5"kcal"

Calculate the enthalpy of formation of sulphuric acid (l) from the fol

1.	Calculate the enthalpy of formation of sulphuric acid (l) from the following data : (i) S(s)+O_(2)(g) to SO_(2)(g),DeltaH=-71.0"kcal" (ii) SO_(2)(g)+(1)/(2)O_(2)(g) to SO_(3)(g),DeltaH=-23.5"kcal" (iii) SO_(3)(g)+H_(2)O(l) to H_(2)SO_(4)(l), DeltaH=-31.2 "kcal" (iv) H_(2)(g)+(1)/(2)O_(2)(g) to H_(2)O(l),DeltaH=-68.5"kcal"
Answer» Solution :From the above EQUATIONS, we have to calculate `DeltaH` for the equation `H_(2)(G)+S(s)+2O_(2)(g) to H_(2)SO_(4)(l),DeltaH-=?` Applying the INSPECTION METHOD, [Eqn. (i)+Eqn. (ii) + Eqn. (III)+Eqn.(iv)], we get, `S(s)+O_(2)(g)+SO_(2)+(1)/(2)O_(2)(g)+SO_(3)(g)+H_(2)O(l)+H_(2)(g) to (1)/(2)O_(2)(g) to SO_(2)(g)+SO_(3)(g)+H_(2)SO_(4)(l)+H_(2)O(l), DeltaH=(-71.0-23.5-31.2-68.5) kcal or `H_(2)(g)+S(s)+2O_(2)(g) to H_(2)SO_(4)(l),DeltaH=-194.2"kcal"`