Question

Arrange the following substances in decreasing order of their boiling points:

• A. Water, ethanol, acetone
• B. Ethanol, acetone, water
• C. Acetone, water, ethanol
• D. Water, acetone, ethanol

Hint:

Boiling point is influenced by the nature of intermolecular forces: hydrogen bonding leads to higher boiling points, while weaker forces like dipole-dipole interactions result in lower boiling points.

Answer 1

The Correct Option is A

The boiling point of a substance depends on the strength of the intermolecular forces between its molecules. The stronger the intermolecular forces, the higher the boiling point. - Water (H2O) has hydrogen bonding, which is a strong intermolecular force. Thus, it has the highest boiling point.
- Ethanol (C2H5OH) also exhibits hydrogen bonding but is weaker than water because of its larger molecular size and lower polarity.
- Acetone (CH3COCH3) has dipole-dipole interactions, which are weaker than hydrogen bonding. Thus, the boiling points decrease in the following order: Water > Ethanol > Acetone.