What is blue cobalt chloride paper and how is it used?

Cobalt chloride paper is used to test for the presence of water leaking through tiny cracks in pipes or porcelain. When water is present, the test paper goes from blue to pink. Heat and humidity are two factors that help determine our outdoor comfort level in summer. read more

Cobalt chloride is an inorganic salt that is bright blue when it is not exposed to humidity. Cobalt chloride paper can be purchased in premade sheets, but it can also be made by dipping paper into a cobalt chloride solution and letting it dry. read more

Making cobalt chloride papers. Procedure. a Dissolve 5 g of hydrated cobalt(II) chloride in 100 cm 3 of water (solution is TOXIC). b Soak filter paper in this solution, drain and dry in an oven (set at no more that 100°C), so that it is a definite blue colour. read more