- The property of being a strong electrolyte is independent of solubility.
- CaO is indeed a very strong alkali, but also the basicity is not directly related to the strength as an electrolyte.
CaO is a ionic substance, that means it is made of ions,
There are as many ionic substances insoluble in water (e.g. alumina,
In all these cases the amount of substance which dissolves in water inlets its positive and negative ions free to get hydrated by water molecules, independently from each other, given that the ions are already existing separately in the ionic lattice.
About the basic (alkaline) behavior, it depends from the specific nature of the ions liberated in water. In this case, the oxide ion
where the stable compound that is slightly soluble in water is the magnesium hydroxyde. It is a strong base too (due to the