When ethanol (C₂H₅OH) is heated with alkaline potassium permanganate (KMnO₄), an oxidation reaction occurs. This reaction leads to the conversion of ethanol into ethanoic acid (acetic acid), accompanied by a color change in the solution.
Reaction Explanation
Alkaline potassium permanganate acts as a strong oxidizing agent. When ethanol is heated with it, ethanol undergoes oxidation, first forming acetaldehyde (CH₃CHO), which then further oxidizes to ethanoic acid (CH₃COOH).
The balanced chemical equation for this reaction is:
C2H5OH+2[O]→CH3COOH+H2OC_2H_5OH + 2[O] \rightarrow CH_3COOH + H_2O
Here, [O] represents oxygen supplied by potassium permanganate (KMnO₄).
Color Change in KMnO₄ Solution
- Initially, potassium permanganate solution is purple due to the presence of MnO₄⁻ ions.
- As oxidation progresses, MnO₄⁻ ions get reduced to MnO₂, forming a brown precipitate in alkaline medium.
- The solution eventually decolorizes, indicating the completion of the oxidation process.
Final Products
- Ethanoic acid (Acetic acid) (CH₃COOH) – A weak organic acid with a sour smell, commonly found in vinegar.
- Water (H₂O) – Formed as a byproduct.
- Manganese dioxide (MnO₂) – A brown precipitate indicating the reduction of KMnO₄.
Applications of This Reaction
- This reaction is an example of the oxidation of alcohols, commonly used in organic chemistry.
- It helps in the identification of primary alcohols (like ethanol) since they get oxidized to carboxylic acids.
- Used in laboratory experiments to study oxidation-reduction reactions.
When ethanol is heated with alkaline potassium permanganate, it gets oxidized first to acetaldehyde and then to ethanoic acid. The color change from purple to brown and ultimately to colorless indicates the reaction progression, making it a useful qualitative test for alcohol oxidation.
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