How do we decide whether salts are weak acids or weak bases?

1 Answer
Apr 8, 2017

Answer:

By the #pH# of the aqueous solution prepared from the salt..........

Explanation:

Weak acids typically give salts that give slightly alkaline solutions.

And weak bases, give salts that give slightly acidic solutions.

#"Sodium carbonate"# is derived from carbonic acid, a WEAK acid, and in solution, this would give a basic solution due to the following equilbrium:

#Na_2CO_3(s) + H_2O rightleftharpoons Na^(+)""^(-)HCO_3 + ""^(-)OH#

And this would give rise to a solution whose #pH>7#. How much more I don't know without quoting details.

Other salts of weak acids include #"Na"_2"HPO"_4#, #"NaF"#, and #"NaO"_2"CCH"_3#: all of these salts would give solutions that were alkaline..........