Expert: Dr. Henry Boyter, Jr. - 1/10/2007

Question
When i said "nature of the salt" i was referring to the degree of dissociation of the salt.NOT its acidic strength in solution. Is it possible To PREDICT this?
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The text above is a follow-up to ...

-----Question-----
Knowing what kind (i.e. strong or weak)of an acid and base a given salt is made of is it always possible to predict the nature (strong or weak) of the salt?

(NOT A HOMEWORK QUESTION)
-----Answer-----
Strong acids with strong bases give almost neutral salts.  Weak acids with weak bases give salts whose strength depends on the difference in Ka and Kb.  A mixed salt is the easiest to tell since the strong part will be almost neutral.  For example sodium acetate comes from NaOH plus acetic acid, so you get a basic solution.  Ac- + H2O = HAc + OH-

Answer
The answer is in general, no you can not predict.  If you have the salt of a strong base and strong acid, the salt will generally be soluble.  If there is a weak acid or base involved, then you have to rely on learning the solubility rules that are given in every beginning chemistry textbook.  The best example is Ba(OH)2.  Form the salt with three STRONG acids, HNO3, HCl, and H2SO4.

BaCl2 and Ba(NO3)2 are soluble, BaSO4 is insoluble.

The rules are just not that clear cut.  For a good solubility table (with additional links)that you should memorize, see:

http://dbhs.wvusd.k12.ca.us/webdocs/Equations/Solubility-Table.html