The purpose is to avoid any contamination of the reagent in the bottle.
because once it has left the bottle it can easily become contaminated.
unwise - foolish
Because usually the sun's light will focus on the glass and will cause a fire. Not a good thing. Definitely not a good thing.
An antonym to unwise sayings would be wise or prudent sayings.
It would be unwise because ANYTHING could of happen to it.
It would be unwise to go hiking in the dark without a flashlight.
unwise
unwise.
It was really unwise to buy a dress on sale without trying it on because I can't return a sale item.
Unwise
The cast of An Unwise Theft - 2007 includes: Ethosheia Hylton as Girl in black
unwise.