The neck. Or if you mean the stopper, the cork, cap., or screwtop.
Because it has alcohol in it , and alcohol evaporates
No, I have never encountered a worm in a bottle of alcohol.
A 70ml bottle of rubbing alcohol would contain approximately 70ml of isopropyl alcohol. Rubbing alcohol typically consists of 70% isopropyl alcohol, so in this case, there would be 49ml of isopropyl alcohol in the 70ml bottle.
The type of alcohol traditionally known to have a worm in the bottle is mezcal.
The plural of bottle top is bottle tops. As in "the bottle tops are plastic".
A bottle will usually state it's alcohol by volume (ABV) as "proof" . Proof is double what the percentage of alcohol is. So, a bottle of 60 proof spirits would be 30% alcohol by volume. The highest percentage alcohol in a spirit that I've seen is 151 proof, and that was a bottle of rum.
No, I have never encountered a bottle with a worm in it while drinking alcohol.
It's called a cap
It is not legal to bottle and sell your own alcohol. You would need to have a liquor license and a business license.Ê
It dilutes the alcohol content.
The top of a water bottle is called a cap
51% typically means 51% by volume. So if you have a 100ml bottle of 51% alcohol, you have 51ml of pure alcohol inside the bottle, diluted to a final solution volume of 100ml.