What color does anhydrous cobalt(II) chloride paper turn when it comes into contact with water?

Anhydrous cobalt(II) chloride is a blue solid. When it is exposed to moisture or comes into contact with water, it undergoes a chemical change and forms hydrated cobalt(II) chloride, which has a pink color. This is a clear example of a color change that indicates the presence of water, making cobalt(II) chloride paper a useful indicator for humidity. The transition from blue to pink demonstrates the compound's ability to absorb water, highlighting its role in detecting moisture levels in the environment. Thus, the correct color change confirming the presence of water is from blue to pink.