Chemical Reactions in Red, White and Blue

Clear solutions of lead nitrate, phenolphthalein, and cupric nitrate are each mixed with ammonium hydroxide to produce striking white, red, and blue colors. The demonstration highlights how chemical reactions can produce new products with different properties, including vivid color changes.

1. Place three 100 ml beakers in a row.
2. Add 15 drops of lead nitrate solution to the first beaker.
3. Add 20 drops of phenolphthalein solution to the second beaker.
4. Add 15 drops of cupric nitrate solution to the third beaker.
5. In a separate beaker, measure about 140 ml of ammonium hydroxide solution.
6. When ready, pour approximately equal amounts of ammonium hydroxide into each of the three beakers.
7. Observe the reactions: one produces a white precipitate, one turns red, and one produces a deep blue complex.

Note that other reactions can be used to produce the colors, see the links below.

Red, White, and Blue Chemical Reactions - Michael Farabaugh:

📄 Chemical Reactions in Red, White and Blue! - Jen Klipfel and Nabila Jachan: https://www.csun.edu/scied/2-chem/old_glory/index.htm

• Use different metal nitrate solutions (such as nickel or cobalt) to produce other vivid colors.
• Swap phenolphthalein with a different pH indicator to create alternative color changes.

• Ammonium hydroxide is highly irritating to eyes and lungs; use in a fume hood.
• Lead nitrate is toxic and a strong oxidant; handle with care and dispose of properly.
• Cupric nitrate is toxic; avoid ingestion and skin contact.
• Phenolphthalein is flammable; keep away from flames and sparks.
• Wear gloves, goggles, and a lab coat at all times.
• Ensure an eyewash station is available nearby.

• What are the reactants and products in each reaction? (Lead nitrate + ammonium hydroxide → lead hydroxide (white precipitate); cupric nitrate + ammonium hydroxide → tetraamminecopper (II) complex (blue); phenolphthalein in base → red color.)
• Why does phenolphthalein turn red in the presence of ammonium hydroxide? (Because phenolphthalein is colorless in acidic solution but becomes pink to red in basic conditions.)
• Why is the lead nitrate reaction especially hazardous? (Lead compounds are toxic and must be handled and disposed of carefully.)
• How can we balance the chemical equations for these reactions?
• Could other chemicals be used to achieve the red, white, and blue effect? (Yes, see the provided links for alternative methods.)