how to identify water using chemical reactions?

Question

i have to describe a logical sequence of chemical reactions that would enable me to identify water
i cant use the boiling point or spectra stuff

i was thinking something along the lines of anhydrous copper II sulphate, but i cant remember what happens or the equation or anything

Answer 1

There is cobalt chloride test paper. One soaks strips of coffee-machine filter paper in aqueous cobalt(II) chloride and dries them out. They are pastel blue. One dips the strips in a medium that is mostly not water. If the strip changes from blue to pink, water is present. In old chemistry sets, the instruction books used to suggest using the strips to predict the weather. Letting the strips lie in the air let them turn from blue to pink to blue again, gauging the humidity.

But also? If you are identifying water in a mixture of other substances, what are the other substances?

Answer 2

This question is much too vague. You want to identify it as being water, AS OPPOSED TO WHAT? pH testing for example, will tell you if the liquid contains acids or bases or not, but will not do anything for example, to identify organic impurities. Various physical and spectroscopic measures would be more definitive, but you specify a chemical test. There is no single chemical test that can unambiguously differentiate pure water from all other possible liquids.

Answer 3

I suggest Cobalt chloride paper. It is paper soaked in cobalt(II) chloride (CoCl2) solution. Equation:
CoCl2 (blue) + 6 H2O → [Co(H2O)6]Cl2 (pink)