Activity 4.5 NCERT Class 10 Science, Carbon and its Compounds

Activity 4.5 NCERT Class 10 Science, Carbon, and its Compounds

Heating alcohol in a water bath with KMnO4
Heating alcohol in a water bath.
Brief procedure:

Activity 4.5 asks us to add alkaline potassium permanganate in warm ethanol and observe the change in colour.


Initially red colour of potassium permanganate disappear. On adding more potassium permanganate red colour prevail.


Potassium permanganate is a strong oxidizing agent. It oxidizes alcohol to acids and reduces itself to manganese dioxide. Potassium permanganate solution is red in colour. Initially, when we add potassium permanganate all potassium permanganate is used up in the reaction. After completion of the reaction, there is no more ethanol in the solution. Adding more potassium permanganate after this endpoint makes the solution red.

Why we use a water bath?

Alcohol is a highly inflammable substance. Heating it directly may lead to an explosion. A water bath is a beaker filled with water. We add the alcohol in a test tube and place it in a beaker. It warms the solution without catching fire.

Next: Reaction of ethanol with sodium. Activity 4.6.

See also: Bunsen Burner design and functions of its components, Activity 4.4.

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