Properties of Solutions- A Visual Demonstration of Raoult’s Law

A Visual Demonstration of  Raoult’s Law

Two photos, each showing two capped test tubes with dark brown liquid appearing at the bottom of the tubes. In the left photo, each tube has an upper yellow layer and a lower brown layer. In the right photo, the left tube contains an upper yellow layer and a lower brown layer. The right tube’s upper and lower layers are yellow.

Description: The intensity of color of bromine vapor is reduced by placing a colorless volatile liquid into the same container.

Source: Journal of Chemical Education – Vol. 67

Year: 1990  Volume: 67  Page: 598

Keywords: Ideal solution, Raoult’s Law, Vapor pressure, Partial pressure, Bromine

Rating:

Hazard: Medium

• Inhalation hazard
• Acute toxicity hazard
• Chemical burn hazard
• Skin corrosion hazard
• Serious eye damage
• Aquatic toxicity hazard
• Flammability hazard

Effectiveness: Good

• Results are observable with guidance
• Good connection from demo to course material
• Clear contrast between behavior of systems
• Time to results is medium
• Good reliability

Difficulty: High

• Careful manipulations required to avoid exposure to reagents
• Use of toxic reagents
• Multi-step procedure with variable results
• Demos in which a display is used
• Prior practice recommended

Safety Precautions:

• Perform in a well-ventilated area, downdraft hood preferred
• Gloves are required
• Eye protection is required
• Chemical spill reagents on hand- Sodium Thiosulfate, 10% solution
• Use UL approved three-prong plug and outlet
• Prevent release of reagents to the environment

Class: Properties of Solutions, Physical Behavior of Gases, Partial Pressure

Division: General, Physical Chemistry

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