To determine the boiling point of a liquid at a given pressure, use a vapor pressure versus temperature graph. According to Figure 10.11, the boiling points are approximately: ethanoic acid - 122 °C at 200 mm Hg, chloroform - 60 °C at 600 mm Hg, and ethanol - 85 °C at 400 mm Hg.
The boiling point of a liquid is determined by its vapor pressure at a specific atmospheric pressure. The vapor pressure of a liquid increases with temperature, and when it equals the atmospheric pressure, the liquid boils. To determine the boiling point of a liquid at a given pressure, you can use a vapor pressure versus temperature graph, such as Figure 10.11. To calculate the boiling point, find the given pressure on the y-axis of the graph and then locate the corresponding temperature on the x-axis.
a. According to Figure 10.11, the boiling point of ethanoic acid at 200 mm Hg is approximately 122 °C.
b. According to Figure 10.11, the boiling point of chloroform at 600 mm Hg is approximately 60 °C.
c. According to Figure 10.11, the boiling point of ethanol at 400 mm Hg is approximately 85 °C.