Groups IV, V, IVB, and VB (14 and 15)- Equilibrium Between Nitrogen Dioxide and Dinitrogen Tetroxide

Equilibrium Between Nitrogen Dioxide and Dinitrogen Tetroxide

Description: Heating and cooling flasks of NO₂ and N₂O₄ shift the equilibrium between the two species. When more NO₂ is produced, the color of gas inside the flask becomes darker.

Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry

Year: 1985    Vol: 2    Page: 180

Ratings:

Keywords: Equilibrium, Dinitrogen Tetroxide, Nitrogen Dioxide, Temperature, LaChatelier’s Principle, Raoult’s Law, Beer’s Law

Hazard: Medium

• Use of toxic gas – sealed vessels
• Demo at non-standard conditions
• Electric shock hazard
• Asphyxiation hazard
• Flammable liquids when acetone bath is used
• Eye irritation
• Cryogenic burn hazard
• Specific organ toxicity – CNS    when acetone bath is used

Effectiveness: Good

• Results are clearly observable with guidance
• Good connection from demo to course material
• Clear contrast between behavior of systems
• Time to results is medium
• Mild effects are seen by audience

Difficulty: Medium

• Physical manipulation of reagents – use of hot bath and cold bath
• Handling of toxic reagents
• Procedure with some intermediate steps
• Temperature dependent results

Safety Precautions:

• Perform in a well-ventilated area
• Eye protection required
• Temperature-resistant gloves required
• Use of UL approved three-prong plug and outlet
• Absorbent material on hand
• ABC fire extinguisher on hand
• Avoid exposure to droplets, mists and vapors
• Handle gas flasks with care

Class: Equilibrium, Gases, Entropy, Thermodynamics, Groups IV, V, IVB, and VB (under 14 and 15)

Division: General, Inorganic Chemistry, Physical Chemistry

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