Concept:For non-polar alkanes, the only intermolecular forces present are London dispersion forces. The strength of these forces increases with the size (molecular mass) and polarizability of the molecule.
Formula:$$ \text{Boiling Point} \propto \text{Molecular Mass / Chain Length} $$
Solution:- All options are straight-chain or branched alkanes.
- As the carbon chain gets longer, the electron cloud becomes larger and more easily distorted (highly polarizable).
- Decane (\( \text{C}_{10}\text{H}_{22} \)) is the largest molecule listed, meaning it has the strongest London dispersion forces.
- Therefore, it requires the most heat energy to separate its molecules, resulting in the highest boiling point.
Why other options are incorrect:Options A (Butane), B (Hexane), and D (Propane) have significantly shorter carbon chains, weaker dispersion forces, and are highly volatile (some are gases at room temperature).
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