The standard enthalpiesof combustion of C_(6)H_(6) (l),C ( graphite) andH_(2)(g) are respectively -3270 kJ mol^(-1), - 394kJ mol^(-1) and-286 kJmol^(-1) . What is the standard enthalpy of formation ofC_(6)H_(6)(l)in kJ mol^(-1) /

The standard enthalpiesof combustion of C_(6)H_(6) (l),C ( graphite) a

1.	The standard enthalpiesof combustion of C_(6)H_(6) (l),C ( graphite) andH_(2)(g) are respectively -3270 kJ mol^(-1), - 394kJ mol^(-1) and-286 kJmol^(-1) . What is the standard enthalpy of formation ofC_(6)H_(6)(l)in kJ mol^(-1) /
Answer» `- 48` `+48` `-480` `+480` Solution :(i) ` C_(6)H_(6)+ ( 15)/(2) O_(2) RARR 6CO_(2)+3H_(2) O, DeltaH= - 3270 kJ mol^(-1)` (ii) `C+ O_(2) rarr CO_(2), DeltaH = -394kJ mol^(-1)` (iii) `H_(2)+(1)/(2) O_(2) rarr H_(2)O,DetlaH=-286kJ mol^(-1)` AIM `: 6C+ 3H_(2) rarrC_(6)H_(6) , DeltaH=?` `6 XX`Eqn. (ii) `+ 3 xx ` Eqn. (iii) -Eqn. (i) ,gives required eqn.with `DeltaH =+ 48 kJ mol^(-1)`