If we were asked to order SO2,H2O,CuO and CaO considering their acidity, how do we find what is more acidic from CaO and CuO?

Answer 1

I would do with the rxn with H2O.
CaO + HOH ==> Ca(OH)2
CuO + HOH --> Cu(OH)2 and Cu(OH)2 is not very soluble in water.

Answer 2

And Ca(OH)2 is also partially soluble in water right?(a white precipitate forms)

And I've heard that as Cu is attracting electrons most Cu compounds are acidic. Is this true?

Answer 3

Yes, Ca(OH)2 is much more soluble than Cu(OH)2
I look at it this. way with Cu salts. CuCl2, for example, the Cl is not hydrolyzed in aqueous solution while the Cu^+2 (actually the [Cu(H2O)4]^2+ is hydrolyzed