1. The problem statement, all variables and given/known data Which solution will have the lowest pH? a) Mg(NO3)2 b) Ca(NO3)2 c) Al(NO3)3 d) KNO3 e) Zn(NO3)2 2. Relevant equations None I know of. 3. The attempt at a solution My reasoning was that when the metal dissociates from the nitrate, it will leave a negative charge on the nitrate. I need to find which one will have the lowest pH, so I figured that the KNO3 would dissociate and leave the NO3 with 1 negative charge, which would only attract 1 hydrogen ion, leaving the least amount of OH ions, meaning the solution would have a lower pH than the other ones, since they would dissociate and attract more hydrogens, leaving more OH ions, which would cause the pH to be higher. But apparently that's not the case. So I'm stumped. Please help.