Reactions of Carbon Dioxide in Aqueous Solution
Description: Tall glass cylinders are filled with basic solutions of indicators. Dry ice is dropped into every other cylinder, and the indicator colors change. One basic pH version of each indicator is used as a reference.
Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry
Year: 1985 Vol: 2 Page: 114
Keywords: Sodium hydroxide, Phenolphthalein, Thymolphthalein, Phenol Red, Universal Indicator, Acidification, Carbonic acid
Rating: 
Hazard: Some
- Cryogenic burn hazard
- Asphyxiation hazard
- Skin corrosion hazard
- Corrosive to metals
- Reproductive toxicity hazard
- Inhalation hazard
Effectiveness: Good
- Results are clearly observable without guidance
- Low failure rate
- Secondary effects
- Time to results is low
- Good connection from demo to course material
- System contrast is noticeable
Difficulty: Medium
- Reactions or demos at non-standard conditions
- Some concerted or timed manipulations
- Procedures with intermediate steps to results
- Use of large glassware
Safety Precautions:
- Eye protection required
- Gloves required
- Cryogenic gloves required
- Perform in a well-ventilated area
- Absorbent materials on hand
- Avoid inhalation of mists or vapors
Class: Acid-Base Reactions, Indicators
Division: General, Analytical Chemistry
Home| General Chemistry Demos| Analytical Chemistry Demos