[tvirus]

Hello everyone.

I am just confused as to which force exactly causes certain mixtures of aqueous solutions to produce insoluble compounds. That is, why is is that some ions are more attracted to water molecules than to other oppositely charged ions that they can combine with? Is it because the electronegativity of the atoms in the water molecule is greater than the electrostatic forces of attraction between ions or something like that?

Any help would be greatly appreciated

[ssadi]

Hello everyone.

I am just confused as to which force exactly causes certain mixtures of aqueous solutions to produce insoluble compounds. That is, why is is that some ions are more attracted to water molecules than to other oppositely charged ions that they can combine with? Is it because the electronegativity of the atoms in the water molecule is greater than the electrostatic forces of attraction between ions or something like that?

Any help would be greatly appreciated

As far as i know, it is like this:
to dissolve ionic crystal
Lattice must be broken and ions separated. (This part is endothermic).
Water molecules gather around each ions. Positive dipoles(H) is attracted to negative ion and negative dipoles(O) is attracted to positive ions and water molecules arrange themselves in that fashion around the ions. (This part is exothermic)
If the total energy change is exothermic, then the solubility is high, and if the total energy change is endothermic, then the solubility is low.
The two energy changes depend on the relative anion and cation sizes.
I gather when the ions are just formed in water, there is a competition between lattice formation (opposite of breaking of lattice) and hydration, result dictated by whichever more exothermic.