OnlineCBT
Chemistry · THERMODYNAMICS
हिन्दीAccording to IUPAC and thermodynamic conventions, the standard molar enthalpy of formation (\( \Delta_f H^\ominus \)) at 298 K and 1 bar is non-zero for which of the following species?
Correct answer · Option A
C(diamond)
Explanation
The standard reference state of carbon is graphite, so \( \Delta_f H^\ominus[\text{C}(\text{graphite})] = 0 \), whereas \( \Delta_f H^\ominus[\text{C}(\text{diamond})] = +1.89\text{ kJ mol}^{-1} \neq 0 \).
