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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 ... 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 has a boiling point of 117.2 °C, which is higher than the temperature of the first fraction collected at 97.2 °C. Therefore, if butan-1-ol were present in the mixture, it would not have evaporated and condensed at 97.2 °C.
Step 3
Provide one reason why the distillation flask should not be heated using a Bunsen burner.
Answer
Using a Bunsen burner could result in an uneven heating of the distillation flask, potentially causing the contents to boil too violently and leading to the risk of splattering or losing valuable fractions.
Step 4
Explain, in terms of intermolecular forces, the difference between the boiling points of these two compounds.
Answer
Butane has only London dispersion forces as its intermolecular forces, while propan-1-ol has both London dispersion forces and strong hydrogen bonding due to the presence of an -OH group. This stronger intermolecular attraction in propan-1-ol results in a significantly higher boiling point compared to butane.