i. ( quad C_ 2 H_ 2 (~g)+O_ 2 (~g) rightarrow CO_ 2 (~g)+H_ 2 O(l) ; Delta H^ circ =-1300 ) ( kJmol^ - ) ii. ( C(s)+O_ 2 (~g) rightarrow CO_ 2 (~g) ; Delta H^ circ =-394 kJmol^ -1 ) iii. ( H_ 2 (~g)+O_ 2 (~g) rightarrow H_ 2 O(l) ; Delta H^ circ =-286 kJmol^ -1 )