Question

Does anyone know why Calcium Hydroxide, Ca(OH)2, does not fully dissociate, yet is still considered a strong base?

Answer 1

Calcium hydroxide is somewhat special, i think just viewing it as a proton acceptor because it has an OH group which is easily attacked by protons it can be considered a strong base. The dissociation shouldnt matter...I think this is enough to explain its strong base character...sorry I dont know much more on the topic

Answer 2

It's really the OH- that forms when any of the hydroxides dissociate that is the strong base. Ca(OH)_2 *supplies* a strong base, just like KOH or NaOH. The different is that Ca(OH)_2 kind of meters it out as it is used up. If there is something to react with the OH- (n acid), it will generally do so to completion. That uses up all the OH- that has been released. Since the solid Ca(OH)_2 must be in equilibrium with *some* amount of dissolved Ca+2 and OH-, more of the solid Ca(OH)_2 will dissolve to re-establish the solubility equilibrium (what you calcualte when you work with Ksp). That will re-establish the supply of strong base (OH-), which can go on to do its strong base thing with whatever acid might be around.