Passage II
Crude oil contains thousands of chemical compounds. To obtain commercially useful compounds, crude oil is distilled in a fractionating tower (see Figure 1). The crude oil is first heated to 400°C in a furnace, then pumped into the fractionating tower. As vapors from the oil rise, they cool and condense. Fractions are collected at different heights in the tower. Each fraction contains a mixture 'of hydrocarbon molecules with similar boiling points. Table 1 shows information about some of the fractions that can be collected. Figure 2 shows the composition of crude oils obtained in 6 different geographic locations.
Figure 1 adapted from American Chemical Society, ChemCom: Chemistry in the Community, 2nd ed. ©1993 by American Chemical Society.
Figure 2 adapted from The New Encyclopaedia Britannica. ©1986 by Encyclopaedia Britannica, Inc.
11. Based on the information in Figure 1 and Table 1, hydrocarbons found in the residue most likely contain:
Your Answer is
Correct Answer is D
Explanation
From table 1 and figure 1, it can be inferred that the more carbon atoms there are, the more they should be on the top layer of the tower, so the residue should contain more carbon atoms than lubricating oil's 16-24, only option D more than 18 carbons per molecule is more in line