Luminol Chemiluminescence

When luminol is mixed with hydrogen peroxide in the presence of sodium hydroxide and potassium ferricyanide, a blue glow is produced. This reaction demonstrates chemiluminescence, where chemical energy is converted directly into light energy without heat.

1. Prepare stock solution A: In a beaker with 100 mL water, dissolve 0.18 g luminol and add 3.0 mL sodium hydroxide solution (1 M).
2. Prepare stock solution B: In another beaker with 100 mL water, add 1 mL hydrogen peroxide (3%) and 0.03 g potassium ferricyanide.
3. Set up a funnel with rubber tubing supported by a ring stand and clamps.
4. Dim the room lights.
5. Pour equal amounts of solution A and solution B into the funnel simultaneously so they mix in the tubing.
6. Observe the bright blue glow produced as the solutions mix; the light should last for several minutes.

How Luminol Works: Chemiluminescence - Chemistry in a Nutshell:

Chemiluminescence of luminol - cold light - Royal Society of Chemistry:

📄 How to make luminol glow - Carolina Knowledge Center: https://knowledge.carolina.com/discipline/physical-science/how-to-make-luminol-glow-glowing-reaction-activity/

• Use a long transparent tube to make the glowing solution more visible to a larger audience.
• Perform the reaction in a darkened room for maximum effect.

• Safety goggles, gloves, and a lab coat required.
• Hydrogen peroxide is a strong oxidizer; avoid skin contact.
• Sodium hydroxide is caustic and can irritate or burn skin; handle carefully.
• Potassium ferricyanide should be handled with care; avoid ingestion and inhalation.
• Do not perform the experiment without proper supervision and protective equipment.

• Why does the luminol reaction produce light instead of heat? (Because the energy from the chemical reaction is released as photons rather than thermal energy.)
• What role does sodium hydroxide play in this reaction? (It provides the alkaline conditions required for luminol to react.)
• Why is a catalyst such as potassium ferricyanide needed? (It speeds up the oxidation of luminol by hydrogen peroxide.)
• How is chemiluminescence different from incandescence? (Chemiluminescence produces light directly from chemical reactions, while incandescence produces light from heat.)