Question

The vapor pressure of acetone at 20o C is 185.5 mm Hg, and the vapor pressure of water at this same temperature is 17.5 mm Hg. Predict which of the two liquids will have a higher normal boiling point and explain why.

Answer 1

The vapor pressure of acetone at 20o C = 185.5 mm Hg

The vapor pressure of water at 20o C = 17.5 mm Hg

Normal boiling point is the temperature at which the vapor pressure of the liquid becomes equal to the atmospheric pressure which is 760 mmHg. higher the vapor pressure, lesser will be boiling temperature. Since the vapor pressure of acetone is higher than that of water, acetone requires less temperature to reach atmospheric pressure(760 mmhg). Thus, the acetone will have the lower boiling point than water.

Thus, water will have higher boiling point than that of acetone.