What do water molecules disassociate in salt crystals when they are dissolved in water?

1 Answer
Mar 4, 2017

I am not quite sure if I follow your question. I will attempt to address what I think you are asking.


When #"sodium chloride, halite,"# is dissolved in water, the water solvent breaks up the solid ionic structure to give so-called #"solvated"# or #"aquated"# sodium and chloride ions:

#NaCl(s)"+ excess "H_2O(l) rarrNa^(+)(aq) + Cl^(-)(aq)#

The #Na^(+)(aq)# species is arguably #[Na(OH_2)_6]^+#, a coordination complex if you like, in which the water molecules bind to the metal centre in an ion-dipole interaction. And likewise, chloride ion is solvated. For these reasons, i.e. ionic bonds are broken, and ion-dipoles, are formed, we could classify this dissolution as an example of chemical change.