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The boiling points of several alkanols are provided in the following table - VCE - SSCE Chemistry - Question 9 - 2010 - Paper 1
Question 9
The boiling points of several alkanols are provided in the following table. Alkanol Boiling point (°C) methanol 64.5 ethanol 78.3 propan-1-ol 9... show full transcript
Worked Solution & Example Answer:The boiling points of several alkanols are provided in the following table - VCE - SSCE Chemistry - Question 9 - 2010 - Paper 1
Step 1
Step 2
By specifically referring to this experiment, explain why the alkanol identified in part i. could not be present.
Answer
Butan-1-ol cannot be present because it has a boiling point of 117.2 °C, which is higher than the first fraction collected at 97.2 °C. If butan-1-ol were included in the mixture, it would have remained in the distillation flask and would not be collected as part of the distillate at that temperature.
Step 3
Provide one reason why the distillation flask should not be heated using a Bunsen burner.
Answer
The distillation flask should not be heated with a Bunsen burner because the flame may be too hot and could cause the contents to boil too violently, increasing the risk of vaporization and possible explosion of flammable vapors.
Step 4
Explain, in terms of intermolecular forces, the difference between the boiling points of these two compounds.
Answer
The higher boiling point of propan-1-ol compared to butane is primarily due to the presence of hydrogen bonding in propan-1-ol. In butane, the predominant intermolecular forces are London dispersion forces, which are weaker than the hydrogen bonds found in propan-1-ol. Consequently, more energy is required to overcome the intermolecular forces in propan-1-ol, resulting in a higher boiling point.