Light Flashes Produced by Oxidation When added to a strong oxidizing agent, ethanol is oxidized and the inorganic product bursts into light

Purpose 1. To demonstrate a two step reaction that ends with an oxidation and flash of light. 2. To show the reactive nature of oxidizing agents with common materials such as alcohol.

Demonstration The experiment occurs in three steps: 1. Creating the mixture in a large test tube: sulfuric acid on bottom, ethanol floats on top, purple crystals of potassium permanganate, KMnO 4, dropped in 2. Sulfuric acid transforms the purple permanganate ion into the highly reactive, green dimanganate ion, Mn 2 O 3 3. As green dimanganate ion forms, it floats back up to the ethanol and oxidizes the alcohol to acetic acid (an ingredient in vinegar). This violent reaction makes a popping flash.

Concepts 1. Oxidation: reaction that molecules undergo to add more oxygen to their structure (this can be very violent!!!) 2. Oxidizing agent: chemical that has the special property of adding oxygen to another molecule 3. Polyatomic Ion: charged group of atoms that are bonded together

Concept 1: Oxidation Definition: reaction that molecules undergo to add more oxygen to their structure Real life examples: Detoxification of chemicals in body Example in experiment: Conversion: ethanol to acetic acid Combustion of paper

Concept 2: Oxidizing Agent Real life example: Oxygen gas (O 2 ) Example in experiment: Dimanganate ion Definition: chemical that has the special property of adding oxygen to another molecule

Concept 3: Ions Definition: a charged atom OR a charged group of atoms that are bonded together---the latter is termed a “polyatomic ion” Real life example: Bicarbonate ion in baking soda Examples in experiment: Permanganate and dimanganate ions

Conclusion The sulfuric acid transforms the purple permanganate ion to form the green dimanganate ion. This in turn floats to the top of the acid and oxidizes (adds oxygen to) ethanol and changes it to acetic acid with a popping flash. In a two-layered mixture of ethanol (on top) and sulfuric acid (on bottom), when potassium permanganate is added...

Comments This demonstration is a very sensitive demonstration and does not always work reliably; this is because water in the ethanol destroys the dimanganate before it can act as oxidizing agent Oxidation reactions are found throughout nature and in your own body. Some can be violent, causing explosions or light flashes, but many are important to life. But, do not try this at home!!

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