Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Acidochromism of 2 in the bulk (a,b), solution (c,d), and as thin film (e–h). a,c,e) pH neutral or basic. b,d,f) pH acidic. g) Film under UV (254 nm) held over an open vial containing HClaq. h) Film under UV (254 nm) held over an open vial containing NH3,aq.
