Soap opera.

Ionic and covalent. Polar and nonpolar. Bonds. And how soap is a great two-timer of water and oil.


soap suds and bubbles1-Minute NomNom

If we try to clean an oily plate with water alone, the oil is not cleaned off. This is because oil and water simply do not mix.  But when you use soap, they mix and make it possible to wash the oil off. Why is this so?

An atomic diagram of water, or H20, showing its protons, neutrons and electrons including the hydrogen and oxygen atoms

Water (H2O) has the characteristics of a polar or ionic compound with positive and negative ends. This is because the electrons are more likely to be found on the oxygen atoms than on the hydrogen atoms and hence the charges are not uniformly distributed. Oil, on the other hand, is a nonpolar or covalent compound. Its electric charges are more evenly distributed.

Olive oil in a glass of water - not mixing

Covalent compounds mix with each other because the atoms slip in between each other and form covalent bonds. Conversely, polar compounds mix with each other because opposite charges on different ends of the atoms attract each other, forming ionic bonds.  Because of these two different ways of bonding, oil and water do not mix.

soap and oil and water on dirty dish

Soap interestingly has both a polar and a nonpolar end (because of something called sodium stearate). When we use soap with water on an oily plate, the polar end is attracted to the water while the nonpolar end slips into the oil.  When we rinse off, the water that runs off pulls the soap molecules along which pull the oil along, giving us a clean plate.

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What other tips do you have to get your greasy plates and pans clean? Share them with us in the comments below!


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photos: in order – depositphotos/volgariveriqonceptyekophotostudiozaschnaus

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