Arrange the following in increasing order of their boiling points:
A. Chloroform
B. Acetone
C. Ethanol
D. Water
E. Mustard Oil
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B, A, C, D, E
The boiling point depends on how strongly the molecules of a liquid hold one another. Liquids whose molecules form hydrogen bonds (ethanol, water) boil higher than those that do not, and heavy oil molecules boil higher still. The boiling points at normal atmospheric pressure are:
B. Acetone — about 56°C; no hydrogen bonds between its molecules.
A. Chloroform — about 61°C; a heavier molecule than acetone, again without hydrogen bonds.
C. Ethanol — about 78°C; its –OH group forms hydrogen bonds.
D. Water — 100°C; each small water molecule can form up to four hydrogen bonds, more than an ethanol molecule.
E. Mustard oil — a mixture of large fat molecules; it begins to smoke at about 250°C, far above the boiling point of water, before it boils.