Question

why do copper vessel turn green with the passage of time?

Answer 1

HeY FriENd HeRe is YoUR AnsWEr :-
It turns green due to chemical reaction with elements. As when we left it unprotected in the open air then it start reacting making a pale green colour layer called Patina.
## HoPe mY anSwEr wILL heLp yOu ##

Answer 2

As iron when exposed to atomosphere form brownish layer
Similarly copper when exposed to atmosphere form green layer and this processing s known as corrosion