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The boiling points of methane, ethane, propane and butane are given - CIE - A-Level Chemistry - Question 4 - 2017 - Paper 1
Question 4
The boiling points of methane, ethane, propane and butane are given. | compound | CH₄ | C₂H₆ | C₃H₈ | C₄H₁₀ | |----------------|-------|-------|-----... show full transcript
Worked Solution & Example Answer:The boiling points of methane, ethane, propane and butane are given - CIE - A-Level Chemistry - Question 4 - 2017 - Paper 1
Step 1
Which statement explains the increase in boiling point from methane to butane?
Answer
The increase in boiling point from methane to butane can be explained by statement C: 'More electrons in the molecules results in stronger van der Waals' forces.' As the size of the hydrocarbon chain increases (from methane to butane), there are more electrons, and consequently, the surface area increases. This leads to stronger London dispersion forces, which are a type of van der Waals' force, as larger molecules have more polarizable electron clouds. Hence, the boiling point increases due to these stronger intermolecular forces.