Concept:The lattice energy of an ionic compound cannot be measured directly through a single experiment. It must be deduced indirectly using Hess's Law via a structured cycle of measurable steps.
Formula:$$ \Delta H_{\text{lattice}} = \Delta H_f - \Sigma (\text{Sublimation}, IE, \text{Dissociation}, EA) $$
Solution:- The Born-Haber cycle was specifically developed by Max Born and Fritz Haber to relate the standard enthalpy of formation of an ionic solid to its component ionic formation steps.
- By substituting the known experimental values into the cycle, one can algebraically solve for the unknown Lattice energy of ionic compounds.
Why other options are incorrect:Covalent compounds do not form electrostatic lattices of ions. Enthalpy of combustion is calculated via bomb calorimetry. Ionization enthalpies are direct inputs
into the cycle, not the final calculated objective.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.