Like “does the Pope shit in the woods?” or “that train has sailed?”
Also, what good examples can you think of?
They are focusing on the dry part of the term. Using a liquid during the process goes against the dry part.
I would tend to disagree with the Cambridge example, because liquids can be dry. “Dry” liquids are anhydrous, meaning they’ve been treated to remove any water.
Source: Am chemist and I teach O-Chem, which frequently uses dry solvents, like anhydrous acetone.
But PERC, the chemical used in “dry cleaning” is NOT a dry liquid, so the existence of dry liquids is also not relevant to their example.
I can’t figure out if the confusion is caused by unfamiliarity with the term dry cleaning, or just a feeble grasp of logic.
PERC
Perchloroethylene (aka tetrachloroethene) is a completely non-polar compound, so, yes, it is a dry liquid.