Which of the following thermochemical equations correctly represents the standard enthalpy of format — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

The standard enthalpy of formation ($\Delta_f H^\circ$) is defined as the enthalpy change when exactly 1 mole of a compound forms from its constituent elements in their most stable thermodynamic reference states. Option A uses diamond instead of graphite. Option C forms 2 moles of product instead of 1. Option D uses $CO$, a compound, rather than elemental carbon. Option B correctly forms 1 mole of $HF$ from reference elemental gases.