How can saline hydrides remove traces of water from organic compounds?
Saline hydrides are ionic in nature. They react with water to form a metal hydroxide along with the liberation of hydrogen gas. The reaction of saline hydrides with water can be represented as:
`AH_(s) + H_2O_(l) -> AOH_((aq)) + H_2(g)`
(where, A = Na, Ca,……)
When added to an organic solvent, they react with water present in it. Hydrogen escapes into the atmosphere leaving behind the metallic hydroxide. The dry organic solvent distills over.
Saline hydrides (i.e, CaH2 NaH etc.) react with water and form the corresponding metal hydroxide with the liberation of H2 gas. Thus, these hydrides can be used to remove traces of water from the organic compounds.
NaH(s) + H2O(l) ———–> NaOH(aq) + H2(g)
CaH2(s) + 2H2O(l) ———> Ca(OH)2(aq) + H2(g)