A chemical plant separates a liquid mixture containing two alkanes by fractional distillation. The mixture is vaporised and fed into the bottom of a fractionating column.
The table gives data at the operating pressure of the column.
| Alkane | Molecular formula | Boiling point in ∘C^{\circ}\text{C}∘C |
|---|---|---|
| X | C7H16\mathrm{C_{7}H_{16}}C7H16 | 98 |
| Y | C12H26\mathrm{C_{12}H_{26}}C12H26 | 216 |
The temperature at outlet M is 150 ∘C150\ ^{\circ}\text{C}150 ∘C.
Explain what happens to each alkane as the mixture rises through the column and why they are collected at different heights. Refer to outlet M in your answer.
131 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.