The standard enthalpy of combustion of ethyne can be estimated from the tabulated bond dissociation — Thermodynamics Chemistry Question
Question
The standard enthalpy of combustion of ethyne can be estimated from the tabulated bond dissociation enthalpies (BDE) shown below to be –982 kJ mol–1. The experimental ∆H°combustion is –1256 kJ mol–1. Which is the best explanation for the discrepancy?
C2H2(g) + 2.5 O2(g) → 2 CO2(g) + H2O(g)
∆H°expt = –1256 kJ mol–1
The tabulated C–H BDE does not account for the unusual strength of the bond formed to the sp-hybridized carbon in C2H2.
The tabulated O=O BDE does not account for the unusual weakness of the bond in dioxygen due to its paramagnetism.
The tabulated C=O BDE does not account for the stabilization due to electronic delocalization in carbon dioxide.
The tabulated O–H BDE does not account for the stabilization due to hydrogen bonding in water.