Physics - Heat & Thermo Question with Solution | TestHub
The latent heat of fusion of a substance is always less than the latent heat of vaporization or latent heat of sublimation of the same substance. Explain.
Evaluate the following statements.
Statement I: Melting always breaks all intramolecular bonds but vaporization breaks none.
Statement II: For common substances in comparable states, vaporization separates molecules much more than melting; the stated ordering is a usual trend, not a universal theorem.
Options:
Answer:
Solution:
Melting only loosens the molecular arrangement; molecules stay in contact, so little work is done against attractions and the volume barely changes. Vaporization must separate molecules completely (breaking nearly all attractions) and also do work pushing back the atmosphere. Sublimation does both melting and vaporization jointly, so is the largest. This comparison is a usual trend, not an unconditional thermodynamic inequality across all states. Statement I is false and Statement II true. Correct option: (C).
