O/N 2020/P12/Q4, O/N 2020/P11/Q4
Petroleum (crude oil) is separated into useful fractions by fractional distillation. The positions at which fractions X and Y are collected from the fractionating column are shown.
Which statement is correct?
A The temperature increases up the column.
B X condenses at a lower temperature than Y.
C X has a higher boiling point than Y.
D X has longer chain molecules than Y.
Answer: B
Explaination:
In fractional distillation, those hydrocarbons (few carbon atoms) have low boiling points and are condensed and collected at the top of the fractionating column. The bigger hydrocarbons are collected at the lower sections of the column.
Hence, fraction X is lighter or smaller (small chain HC) than Y (which is heavier with bigger chain HC) that’s why fraction X condensed and collected at the top of the column having low temperature.
