Question

The vapor pressure of ethanol is 58.7 torrat 25 °C. Determine the vapor-pressure lowering. AP, of an ethanol solution that contains 0.125 mol sucrose dissolved into 1.545 mol ethanol.

A. 0.925 torr
B. 2.13 torr
C. 4.4 torr
D. 12.4 torr
E. 54.3 torr

Answer 1

The vapor-pressure lowering for the ethanol solution with sucrose is calculated using Raoult's law and the mole fraction of ethanol. The correct answer is 4.4 torr.

Step-by-step explanation:

To determine the vapor-pressure lowering (ΔP) of an ethanol solution with sucrose dissolved, we can use Raoult's law which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent. Initially, we are given that the vapor pressure of pure ethanol is 58.7 torr at 25 °C. The mole fraction of ethanol in the solution can be calculated using the number of moles of ethanol (1.545 mol) and the number of moles of sucrose (0.125 mol).

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The answer is C. 4.4 torr, which is the vapor-pressure lowering for the ethanol solution due to the addition of sucrose.