Question

Water turns blue cobalt chloride paper:

• A. no change
• B. red
• C. pink
• D. orange

Answer 1

Answer: (C)

pink

Cobalt chloride, $CoC{l}_2$, is a fascinating compound that changes color in response to humidity. As humidity increases, cobalt chloride changes color from sky blue to purple to pink. Such striking changes in color make cobalt chloride useful as a humidity indicator in weather instruments.