During complete combustion of one mole of butane, 2658 kJ of heat is released. The thermochemical reaction for above change is

(i) 2C₄H₁₀(g) + 13O₂(g) → 8CO₂(g) + 10H₂O(l) ∆_c H = –2658.0 kJ/mol

(ii) C₄H₁₀(g) $\frac{13}{2}$ +  O₂ (g) → 4CO₂ (g) + 5H₂O (g) ∆_c H = –1329.0 kJ/mol

(iii) C₄H₁₀(g) $\frac{13}{2}$ +  O₂ (g) → 4CO₂ (g) + 5H₂O (l) ∆_c H = –2658.0 kJ/mol

(iv) C₄H₁₀ (g) $\frac{13}{2}$ + O₂ (g) → 4CO₂ (g) + 5H₂O (l) ∆_c H = +2658.0 kJ/mol