posted by john peterson on .
I was asked to consider the solubility for hydrated calcium sulfate in HCl.
The principal acid my proffesor had posted for the solution was [ CaSO4(hyrdrated) + HCl <--> H30^+ + Ca^2+ + SO4^2- ]. I guess what I'm asking is what happened to the Cl^- and why isn't it reacting with Ca^2+ to produce CaCl2. ? It's not a spectator ion right??? But if it is why?
It is a spectator ion, the chloride ion is in solution on both sides. CaCl2 is ionic, and is in ions in water solution.
correction: sulfate ion should be hydrogen sulfate ion
Yes, it is a spectator ion. Why? Because CaCl2 is soluble (it isn't a precipitate), it isn't a gas, and it isn't a weakly ionized substance. CaSO4 is more soluble in HCl than it is in water BECAUSE of k2 for H2SO4; i.e., HSO4^- = about 10^-2.