[posix_memalign]

Given a set of arbitrary compounds, how can it be determined which of said compounds have the lowest solubility in water?

E.g. if the compounds were, K3PO4, Fe(NO3)2), Hg2Cl2, Na2CO3, CuCl2; how would it be determined that Hg2Cl2 is the compound that has the lowest solubility in water?

Thanks in advance!

[nj_bartel]

http://www.csudh.edu/oliver/chemdata/solrules.htm

[posix_memalign]

http://www.csudh.edu/oliver/chemdata/solrules.htm

Thanks, nice set of notes, but I don't see that the notes entail any information in regard to determine which compound, among a set of compounds is the _most_ or the _least_ soluble? How would that be determined?

[nj_bartel]

There isn't.  However, out of all of the compounds you listed, every single one, except for Hg2Cl2, falls into the 'soluble' category.  Hg2Cl2 has an exception made for it and it is noted as one of the few insoluble metal chlorides.

[BluRay]

Thanks, nice set of notes, but I don't see that the notes entail any information in regard to determine which compound, among a set of compounds is the _most_ or the _least_ soluble? How would that be determined?

There isn't a simple rule, chemistry in cases like this reveals its empirical nature: you have to know some results.

Anyway, with time, you will learn that:

1. K₃PO₄ is soluble, because there are just a few insoluble compounds of potassium and this one is not in the list. Or: phosphates of alcaline metals are soluble (apart from Li).

2. Fe(NO₃)₂  (but are you sure is not Fe(NO₃)₃  instead?) is certainly soluble because all nitrates are.

3. Na₂CO₃ is soluble because, apart from lithium, carbonates of alcaline metals are very soluble.

4. We are left with CuCl₂ and Hg₂Cl₂. Often, Cu²⁺ salts are soluble and Hg₂²⁺ are insoluble, but it's not a rule, so you have to know which are and which aren't.