Consider the following chemical equations: 2NO2(g) → 2NO(g) + O2(g) ΔHf = +14 kJ mol⁻¹ NO(g) + CO(g) → CO2(g) + NO(g) ΔHf = -226 kJ mol⁻¹ 2NO(g) → N2O4(g) ΔHf = -57 kJ mol⁻¹ N2(g) + O2(g) → 2NO(g) ΔHf = +181 kJ mol⁻¹ Which one of the following graphs is consistent with the chemical equations above? - VCE - SSCE Chemistry - Question 18 - 2021 - Paper 1

This reaction has a significantly negative enthalpy change (-226 kJ mol⁻¹), indicating it is highly exothermic. The graph should show a notable dip in enthalpy as the reaction progresses.

This reaction is exothermic with a negative enthalpy change (-57 kJ mol⁻¹), suggesting that the graph should show a decrease in enthalpy upon formation of the products.

This reaction has a positive enthalpy change (+181 kJ mol⁻¹), indicating an endothermic process. The graph will depict an increase in enthalpy from reactants to products.

Given that the endothermic and exothermic reactions reflect a combination of enthalpic changes, graph C, which shows one endothermic and one exothermic process, is consistent with the chemical equations. Thus, the answer is C.