Introduction
In this experiment, we will determine the efficiency of light produced by luminol in an aqueous solution of hydrogen peroxide in which hydrogen peroxide acted as an oxygen donor and iron acted as a catalyst. This chemical reaction that releases light is known as Chemiluminescence.
Aim
To determine the efficiency of light produced by luminol in an aqueous solution of hydrogen peroxide.
Theory
1. The release of energy from a chemical solution generates electromagnetic radiation as light, and this radiation is termed Chemiluminescence.
2. The commonly termed chemiluminescence reaction is the one that contains highly oxidized species such as peroxide.
3. Luminol is an organic chemical that emits light on oxidation. It performed a phenomenon called luminescence.
Requirements
1. Luminol
2. Calorimeter
3. 3-nitrophthalic Anhydride
4. Hydrazine Sulfate
5. Hydrated Sodium Acetate
6. Glycerol Boiling Chip
7. Thermometer
8. NaOH (10% solution)
9. Sodium Hydrosulfite
10. Glacial Acetic Acid
11. Potassium Ferricyanide [K3Fe(CN)6]
12. Hydrogen Peroxide (3%) (commonly obtained)
13. HCL Laptop
14. Vernier Lab Equipment (Lab Pro, Digital Thermometer, Light Meter)
Procedure
Step 1: Produce luminol in your chemistry lab.
Step 2: Divide this luminol into two parts of equal amounts for performing two separate reactions.
Step 3: Perform the first reaction in a calorimeter.
Step 4: Measure the total energy evolved.
Step 5: Perform the second reaction in a glass beaker in a dark room.
Step 6: Now, measure the luminescence emitted by this experiment.
Step 7: Convert this luminescence into light energy.
Step 8: Divide the light energy by the total energy emitted by luminol. This will result in the efficiency of light produced.
Step 9: Record your observations.
Observation
1. We observed that at least 0.0180% of the energy generated by luminol gets converted into light.
2. More light might be created, but this only goes for heating the solution or getting transformed into heat.
Result
1. 0.0180% of the energy generated by the solution of luminol will escape the solution in the form of light.
2. There were many things to learn from this experiment, like how to perform a good experiment, chemiluminescence, and light conversion.
Precaution
1. Use glasses and gloves to perform this experiment.
2. Wash your hands thoroughly after the experiment.
3. Record your observation carefully.
Conclusion
In this experiment, we determined the percentage of energy produced by luminous solutions that get converted into visible light.
VIVA Questions With Answers
Q.1 What was the aim of your experiment?
ANS. To determine the efficiency of light produced by luminol in an aqueous solution of hydrogen peroxide.
Q.2 What is the percentage of energy produced by luminol that gets converted into visible light?
ANS. 0.0180% of the energy generated by the solution of luminol will escape the solution in the form of light.
Q.3 Where is chemiluminescence used nowadays?
ANS. Chemiluminescence is used in pharmacological testing, protein blotting, toxicology testing, and immunoassay.
Q.4 What do you understand about luminol?
ANS. Luminol is an organic chemical that emits light on oxidation. It performed a phenomenon called luminescence.

Saquib Siddiqui is a Mechanical Engineer with expertise in science projects and experiments. Saquib’s work focuses on integrating scientific concepts with practical applications, making complex ideas accessible and exciting for learners of all ages. In addition to his practical work, Saquib has authored several articles, research papers, and educational materials.
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