How to make a glowing fountain using luminol and hydrogen peroxide

Making a glowing fountain using luminol chemiluminescence

Safe­ty pre­cau­tions

Wear pro­tec­tive gloves, eye­wear, and a mask. Per­form this ex­per­i­ment in a well-ven­ti­lat­ed area.

Reagents and equip­ment

  • 2 g sodi­um car­bon­ate;
  • 0.1 g lu­mi­nol;
  • 12 g sodi­um bi­car­bon­ate;
  • 0.25 g am­mo­ni­um car­bon­ate;
  • 0.2 cop­per(II) sul­fate;
  • 500 mL dis­tilled wa­ter;
  • 250 mL 3% hy­dro­gen per­ox­ide so­lu­tion;
  • 15 mL 25% am­mo­nia so­lu­tion;
  • 3 g sodi­um hy­drox­ide;
  • one 500 mL beaker;
  • two 250 mL beakers;
  • one 2 L con­i­cal flask;
  • one 100 mL con­i­cal flask;
  • a stop­per with 3 tubes;
  • a mag­net­ic in­duc­tion stir­rer and stir­ring bar;
  • a stand;
  • one sy­ringe con­tain­ing 25 mL wa­ter.

Step-by-step in­struc­tions

Place the 1 L beaker on the mag­net­ic in­duc­tion stir­rer and place the stir­ring bar in­side. Add, in or­der: 500 mL dis­tilled wa­ter, 2 g sodi­um car­bon­ate, 0.1 g lu­mi­nol, 12 g sodi­um bi­car­bon­ate, 0.25 g am­mo­ni­um car­bon­ate, 0.2 g cop­per(II) sul­fate. Stir un­til ful­ly dis­solved to ob­tain the lu­mi­nol so­lu­tion. The so­lu­tion should turn green. Fix the 2 L con­i­cal flask up­side down in the stand and fill with gaseous am­mo­nia. To do this, pour 15 mL 25% am­mo­nia so­lu­tion into the 100 mL con­i­cal flask. Add 3 g sodi­um hy­drox­ide. In­sert the neck of the small flask into the neck of the large flask un­til you can smell the sharp odor of am­mo­nia. Im­me­di­ate­ly close the large flask us­ing the stop­per with three tubes. Fill one 250 mL beaker with 3% hy­dro­gen per­ox­ide so­lu­tion, and the oth­er with the lu­mi­nol so­lu­tion you pre­pared. Put two of the stop­per tubes in these beakers – and keep in mind that these tubes are con­nect­ed by an adapter. Con­nect the third tube to the sy­ringe con­tain­ing 25 mL of wa­ter. In­ject the wa­ter, turn out the lights, and watch the lu­mi­nous foun­tain in the flask!

Process de­scrip­tion

The re­lease of light as the re­sult of a chem­i­cal re­ac­tion is known as chemi­lu­mi­nes­cence. Lu­mi­nol has the abil­i­ty to re­lease light when ox­i­dized by an ox­i­diz­ing agent such as hy­dro­gen per­ox­ide. Cop­per(II) ions al­low for hy­dro­gen per­ox­ide to dis­so­ci­ate into oxy­gen and wa­ter; they also cat­alyze the ox­i­da­tion of lu­mi­nol by this oxy­gen in a ba­sic medi­um. Lu­mi­nol turns into an un­sta­ble par­ti­cle, which re­leas­es light as it re­turns to a sta­ble form.

С₈H₇N₃O₂ + 2OH⁻ ⇄ C₈H₅N₃O₂²⁻ + 2H₂O

2H₂O₂ + Cu²⁺(cat­a­lyst) = O₂ + 2H₂O

C₈H₅N₃O₂²⁻ + O₂ + Cu²⁺(cat­a­lyst)= С₈H₇NO₄²⁻ + N₂ + blue light

When sodi­um hy­drox­ide dis­solves, it re­leas­es heat, which low­ers am­mo­nia’s sol­u­bil­i­ty in wa­ter. Since am­mo­nia is lighter than air, it fills the flask and forces the air al­ready in the flask out.

The am­mo­nia in the flask then be­gins to dis­solve in the wa­ter that we “in­ject” us­ing the sy­ringe. The pres­sure lev­el in the flask low­ers, and the so­lu­tions in the beakers are drawn into the flask. Their com­po­nents min­gle, re­act, and cre­ate the glow­ing foun­tain you see.