IMSO 2021 Science International - Theory I Question 20

Question 20

(20) Steam distillation is used to extract limonene, a volatile essential oil, from oranges. In steam distillation, a flask containing water is heated to form steam. The steam then enters another flask with the orange peelings. Finally, limonene and water are collected at the receiving flask. Steam allows the limonene to boil at a lower temperature and carries its vapor with it.

Which of the following statements is the main reason why steam distillation is used to extract limonene? [1.5 marks]

1. Because steam has greater kinetic energy than water, steam distillation can extract limonene faster than in simple distillation.
2. Because the initial amount of water is greater in the first flask, steam distillation can extract more limonene than in simple distillation.
3. Because limonene and water is immiscible, the distillate can be separated easily.
4. Because the peelings contain both volatile and non-volatile compounds, steam distillation only extracts limonene without extracting the rest of the non-volatile materials.