Question

Give an example where removal of water molecule from a substance change it's colour. what will happen if the water removed is restored in the same amount? ​

Answer 1

Hydrate, any compound containing water in the form of H2O molecules, usually, but not always, with a definite content of water by weight. The best-known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water. Exceptions to this are the zeolites (aluminum silicate minerals or their synthetic analogues that contain water in indefinite amounts) as well as similar clay minerals, certain clays, and metallic oxides, which have variable proportions of water in their hydrated forms; zeolites lose and regain water reversibly with little or no change in structure.

zeolite; hydrate