I know that, solubility of alkaline earth metal hydroxides increases down the group and solubility of alkaline earth metal sulfates decreases down the group.
I wish to understand the reason for these trends.
Answer
A few weeks ago I would have given the hard soft acid base theory (HSAB) explanation.
I have heard this "trend" explained in this way: Hydroxide is hard and sulfate is soft. So, the harder ions are, the more soluble with sulfate and less with hydroxide.
About a week ago I was playing around with some DH, lattice energy, and Ksp data and I found that barium seems to go against the "trend".
I found these posts that show that many of the "trends" we are taught in chem class aren't as trendy as we are told.
Look at this: http://www.chemguide.co.uk/inorganic/group2/solubility.html
Is this a homework question or a curiosity question? If the former, the "trend" isn't that trendy and the teacher should read the links above. If the latter, do you know that barium salts tend to go against the "trend"?
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