5.9 Chemiluminescence--Luminol

Chemical Concept Demonstrated: Chemiluminescence

Demonstration:

Solution A

  • Dissolve Na2CO3 in distilled water
  • Add luminol, NaHCO3, (NH4)2CO3, and CuSO4 * 5H20
  • Dilute with water

Solution B

  • Dilute 3%H2O2 with distilled water

Pour solutions A and B simultaneously into the funnel.


Observations:

    The entire spiral gives off a singular glow.

Explanation:

    Luminol is converted to a dianion in basic solution.  This dianion is then oxidized with H2O2/Cu2+ to form N2 and an aminophthalate ion in an electronically excited state.  In order to achieve an electronically unexcited state, the ion emits a photon of wavelength 424 nm.