What is the correct order of evaporation?

The Fastest to Evaporate: Petrol, Alcohol, Kerosene, and Water

When it comes to evaporation, not all liquids behave the same way. The speed at which a liquid turns into vapor depends largely on the strength of its intermolecular forces — the invisible forces that hold molecules together. The weaker these forces, the faster the liquid evaporates.

This explains why petrol evaporates almost instantly when exposed to air. Its molecules are held together by very weak forces, allowing them to escape into the atmosphere with ease. That’s also why you can smell petrol so quickly — its vapors are already in the air.

Next in line is alcohol, commonly seen in hand sanitizers or rubbing solutions. Alcohol evaporates quickly, though not as rapidly as petrol. Its intermolecular forces are slightly stronger than petrol’s, but still weak enough to allow fast evaporation — which is why cold alcohol on your skin creates a brief cooling sensation.

Then comes kerosene oil. It’s slower to evaporate because its molecules are more strongly attracted to each other. You might have noticed that spilled kerosene lingers longer on surfaces compared to alcohol, leaving behind an oily residue before fully evaporating.

Finally, there’s water. Despite being a relatively simple molecule, water has surprisingly strong hydrogen bonds — a type of intermolecular force that makes it resistant to evaporation. That’s why a glass of water left out takes hours or even days to dry up, while petrol vanishes in minutes.

So the correct order of evaporation — from fastest to slowest — is: petrol > alcohol > kerosene oil > water. This simple hierarchy reveals how molecular attraction shapes everyday experiences, from fuel handling to drying time on your skin.