Which option below describes a chemical property of a substance? A. the chlorine gas was a yellow-green color at room temperature
B. The liquid mercury boiled at a temperature of 630 K
C. The iron nail became rusty when exposed to water and air
D. The solid silver was shiny and nearly white in color.

C

Explanation:

Rust is a chemical change (reaction) all of the other options only change the state meaning that it is a physical reaction.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.