Amphiprotic anions

For the acid-base properties of amphiprotic anions such as HCO3 otHJPOt. see the discussion at the end of this section. 

A similar argument can be used to decide whether an amphiprotic anion such as HC03 or H2PO4- is acidic or basic. In principle, these ions can act as either weak acids or weak bases ... 

At the first stoichiometric point of the titration, aii the diprotic acid has been converted to its conjugate base, H A. This amphiprotic anion can react with itseif, analogous to the self-ionization of water ... 

At intennediate pH values, the solution contains a relatively high concentration of the amphiprotic anion HA". 

The reactions of salts in water become more complicated if the salt in question is amphiprotic, i.e. can function both as an acid and a base. Examples of amphiprotic anions are bicarbonate (sometimes called hydrogen-carbonate), HCOy, and bisulfite (or hydrogensulfite), HSOj. These species can donate or accept H+ ions in solution. 

Predicting Whether the Solution of an Amphiprotic Anion Is Acidic or Basic... 

Salts Hiat Yield Neutral Solutions 604 Salts Hiat Yield Acidic Solutions 604 Salts Tbat Yield Basic Solutions 604 Salts of Weakly Addic Cations and Weakly Basic Anions 605 Salts of Amphiprotic Anions 605... 

The further question we need to tackle is the pH of a solution of a salt with an amphiprotic anion, such as a solution of NaHC03. Is the solution acidic on account of the acid character of HCO3 or is it basic on account of the anions basic character As we show in Further information 4.2, under the circumstances specified there (iC 2 K i, S KJK 2> and S K i), where S is the numerical... 

The aim is to calculate the pH of a solution of a salt MHA, where HA" is an amphiprotic anion (HCOj is an example). We consider the foUowing two equilibria ... 

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