GKFix MCQ Question

Which of the following reactions is an example of an exothermic process?

• A. CaCO3(s) → CaO(s) + CO2(g); ∆rH° = +178.3 kJ mol–1
• B. C(graphite, s) + 2H2(g) → CH4(g); ∆fH° = –74.81 kJ mol–1
• C. C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l); ∆rH° = –1367 kJ mol–1
• D. H2(g) + ½Br2(l) → HBr(g); ∆fH° = –36.4 kJ mol–1