Topic: Sublimation.
Why do mothballs disappear over time?
Wow.
You have a nice collection of clothes.
But have you kept mothballs to protect them?
I had kept them a few months back below these clothes.
Hey, where did the mothballs go?
I had placed them right here.
Did you steal them?
No No.
I haven't stolen anything.
Mothballs disappear over time.
Do you know why?
It is because of a process called sublimation.
During sublimation, a solid on heating.
Converts directly into vapor without passing through the intermediate liquid state.
Don't lie.
How is that even possible?
See, I also hid a burger here many days ago.
It did not disappear.
Gross.
Just throw that burger in the dustbin.
Not all substances sublimate.
Mothballs are made up of naphthalene.
Naphthalene has very weak intermolecular forces.
Because of these weak forces.
The mothball which is made up of naphthalene sublimates.
It changes its state from solid to vapor.
Now, this vapor is either absorbed by the fabric.
Or it escapes into the atmosphere causing the mothballs to disappear over time.