Question

When you heat a hydrated substance what is driven off through the process of evaporation?

Answer 1

The simple answer is WATER...

Explanation:

Most inorganic chemists go to a great deal of time and trouble driving off the water bound to metal hydrates, and producing anhydrous salts. And of course they have to carefully dry their solvents, if they want to do a reaction in anhydrous conditions....

`MX_2*6H_2O + Delta rarr MX_2(s) + 6H_2O(l)uarr`

There are some reagents we can use that accomplish this chemically...i.e. the metal hydrate could be heated at reflux in the presence of trimethylsilyl chloride and THF....

`MCl_2*6H_2O(s) + 12Me_3SiClstackrel(Delta,THF)rarr Cl_2M*(THF)_n + 6Me_3SiOSiMe_3(l) + 12HCl(g)uarr`

Thionyl chloride could also be used...