Fizzing and Foaming: Reactions of Acids and Carbonates
Description: A mixture of soap, bicarbonate, methyl red indicator and water is placed in a soda glass or 1L tall form beaker and treated with 6M HCl. The mixture fizzes, foams, and changes color from yellow to pink as it overflows the glass.
NaHCO3(aq) + HCl(aq) → H2O(l) + CO2(g) + NaCl(aq)
Source: UW Card Catalog, Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry
Year: 1989 Vol: 3 Pages: 96 – 99
Keywords: Acid Base reactions, Carbonates, Gas producing reactions, Indicators
Rating: 
Hazard: Low
- Skin corrosion hazard
- Inhalation hazard
- Serious eye damage
- Corrosive to metals
- Specific organ toxicity hazard – single exposure – respiratory system
Effectiveness: Average
- Some connections from demo to course material
- Time to results is low
- Results are observable without guidance
- Contrast between systems behavior is clear
- Mild effects are observed by audience
- Some secondary effects
- Good reliability
Difficulty: Low
- Simple procedures
- Simple manipulations for most to perform
- Use of gas-producing reagents
Safety Precautions:
- Eye protection required
- Gloves required
- Avoid exposure to vapors, mists, or gases
- Spill material on hand
- Extra sodium bicarbonate on hand
Class: Acids and Bases
Division: General
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