Peeling An Egg With The Use of Vinegar

Hello everyone!

We are going to share an interesting experiment about how acids can be used in real life applications. This one involves peeling an egg with the aid of a weak acid. Read on!

Dissolving an egg in vinegar is a classic experiment folks can perform with younger children. If you want less of a mess you can always use a hard-boiled egg (though using a raw egg is a bit cooler).

Soaking the egg in vinegar initiates a chemical reaction that dissolves its calcium carbonate shell, subsequently releasing carbon dioxide gas which appear as bubbles on the outside.

What actually happens to the egg shell?

Insoluble calcium carbonate (CaCO3) crystals which constitute almost the whole egg shell has reacted with vinegar - an aqueous 4% acetic acid solution (CH3COOH). As a result, soluble calcium acetate (Ca(CH3 COO)2) is formed. The gas bubbles produced in the process is carbon dioxide (CO2), excluded from the carbonate by the acid. This is described by the following chemical reaction equation:

CaCO3 + 2CH3COOH → Ca(CH3COO)2 + CO2↑ + H2O

As a result, we are left with an egg stripped entirely of its hard shell. Only one thin matte film which possesses a texture similar to parchment paper remains intact. While this is sufficiently sturdy to hold the liquid contents inside, nevertheless a certain fragility exists. Therefore, the egg should be handled with great care. If it is dropped or inadvertently squeezed, be prepared to do unscheduled cleaning!


The above content is contributed by Dr Aw Junxin, owner as well as IB and 'N'/'O'/'A' Level Chemistry tutor at Uptas Learning Hub.


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