In the classroom, I often see alcohol wipes being used to erase both water based and oil based markers. But here’s the question, how does a single-molecule substance like alcohol dissolve both water-based and oil-based solutes when most liquids can only dissolve one of the two?
In: Chemistry
Well the wipes almost certainly have more water than alcohol in them but the actual reason is probably because the marker being erased hasn’t fully dried yet and could be wiped away be almost anything absorbent.
Alcohols are typically a chain (or branched chain) of hydrocarbons with an OH at one end.
So they have one end that looks kind of like fats/oils (hydrocarbon chains) and one end that looks kind of like water (H-OH). Which makes them somewhat receptive to both types of substances.
There are three things that make alcohol a good cleaner:
* It’s a small molecule, it can get in and under the big complex shaped molecules in colored things.
* The alcohol end is **just like water!** So it does good at cleaning the things water can. Like white glue and wet erase markers.
* Thee other end is a lot like a small **soap**, and so it can clean a lot of those things too. Like paint markers and peanut butter stains.
{edit to add) The paper in the wipes also helps rub things off, but that’s not special about alcohol, it’s just scrubbing.
Bonus question: How are alcohols different from soaps?A soap is a “salt” of oil, and alcohol replaces the salt end with a water end. That’s why it’s different from soap. And why they sometimes clean different things.
Alcohol is a little in-between. It can’t dissolve salts the way water can, but on the other hand it can dissolve oils and greases to some extent.
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