Water molecules separate, surround and disperse the ions into the liquid.
Some ionic compounds are only slightly (sparingly) soluble in water. e.g. silver chloride. This is because the electrostatic attractions within the compound are greater than the attraction between the ions and the water molecules
All ionic compounds will dissolve to a certain extent even though we call them insoluble
C C H H H H H H O + Polar substances will dissolve in ethanol which has a polar and a non-polar part. Water and ethanol are therefore miscible. Note the ethanol and water do not dissociate into ions! - + + - H H - O
In precipitation reactions two soluble compounds react to form an insoluble product, a precipitate. Precipitates form because the electrostatic attraction between the ions outweighs the tendency for the ions to become solvated (surrounded by the solvent molecules) and move randomly through the solution.
You can predict whether a precipitate occurs by considering the solubility of the products.
Not all bases actually contain OH -. Ammonia NH 3 is a covalent gas that reacts with water to produce a basic solution. It is a weak base i.e. the following reaction does not go to completion but is in equilibrium. Both forward and backward reactions are occuring at the same rate .
NH 3 + H 2 O NH 4 + + OH -
Ammonia removes a proton from water to leave OH - ion