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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 boiling point/K CH₄ 112 CH₃CH₃ 185 CH₃CH... 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 correct answer is C: More electrons in the molecules results in stronger van der Waals' forces.
As the number of carbon and hydrogen atoms increases from methane to butane, the number of electrons in each molecule also increases. This leads to greater induced dipole interactions, known as van der Waals' forces. Consequently, the boiling points of these alkanes increase due to the stronger intermolecular forces that must be overcome to change from liquid to gas.