Nomenclature of Acid Anions

In Unit VI you learned that acids generally have one or more H at the front of the formula. It does not have a charge because we have added as many H⁺ as necessary to keep it neutral. An "acid anion", however, by definition must have a H in front (to be called an acid), as well as a negative charge (to be called an anion). It is derived from having added less than the necessary number of H⁺.

For example, if we add only one H⁺ to the sulfate ion (SO₄^{2- )},we would have the acid anion, HSO₄^-. If we add only one H⁺ to the phosphite ion (PO₃^3-), we would have the acid anion HPO₃^2-. If we added two, we would have the acid anion H₂PO₃^-. Note that the negative charge of the anion is reduced by each additional H⁺.

Study the following names and formulas and then test yourself using flash cards:

CO3^2^- carbonate	PO4^3^- phosphate	PO3^3^- phosphite
HCO3^- hydrogen carbonate  or bicarbonate	HPO4^2^- hydrogen phosphate	HPO3^2^- hydrogen phosphite
SO4^2^- sulfate	H2PO4^- dihydrogen phosphate	H2PO3^- dihydrogen phosphite
HSO4^- hydrogen sulfate or bisulfate
SO3^2^- sulfite
HSO3^- hydrogen sulfite or bisulfite

Drill M: Nomenclature of Acid Anions

	Formula	Stock Name	Common Name  (when appropriate)
1	Ca(HCO3)2
2	Fe(HCO3)2
3	Pb(HPO4)2		xxxxxxxxxxxxxxxxx
4	AgHSO3
5	Bi(H2PO3)3		xxxxxxxxxxxxxxxxx
6		barium hydrogen phosphate	xxxxxxxxxxxxxxxxx
7		magnesium hydrogen sulfite
8		aluminum hydrogen phosphate	xxxxxxxxxxxxxxxxx
9		mercury(II) dihydrogen phosphite	xxxxxxxxxxxxxxxxx
10		zinc(II) hydrogen carbonate
11			barium bisulfite
12			iron(III) bicarbonate
13			copper(I) bisulfate
14			copper(II) dihydrogen phosphite
15		tin(IV) hydrogen phosphate	xxxxxxxxxxxxxxxxx
16		antimony(III) hydrogen phosphate	xxxxxxxxxxxxxxxxx

To check your answers, note that you are at Drill M

Answers to Drill M: Nomenclature of Acid Anions

	Formula	Stock Name	Common Name (when appropriate)
1	Ca(HCO3)2	calcium hydrogen carbonate	calcium bicarbonate
2	Fe(HCO3)2	iron(II) hydrogen carbonate	iron(II) bicarbonate
3	Pb(HPO4)2	lead(IV) hydrogen phosphate lead(IV) monohydrogen phosphate	xxxxxxxxxxxxxxxxxx
4	AgHSO3	silver(I) hydrogen sulfite (Ag is usually 1+, so (I) is usually left out.)	silver(I) bisulfite (Ag is usually 1+, so (I) is usually left out.)
5	Bi(H2PO3)3	bismuth(III) dihydrogen phosphite	xxxxxxxxxxxxxxxxxx
6	BaHPO4	barium hydrogen phosphate	xxxxxxxxxxxxxxxxxx
7	Mg(HSO3)2	magnesium hydrogen sulfite	magnesium bisulfite
8	Al2(HPO4)3	aluminum hydrogen phosphate	xxxxxxxxxxxxxxxxxx
9	Hg(H2PO3)2	mercury(II) dihydrogen phosphite	xxxxxxxxxxxxxxxxxx
10	Zn(HCO3)2	zinc(II) hydrogen carbonate  (Zn is usually 2+, so (II) is usually left out)	zinc(II) bicarbonate (Zn is usually 2+, so (II) is usually left out)
11	Ba(HSO3)2	barium hydrogen sulfite	barium bisulfite
12	Fe(HCO3)3	iron(III) hydrogen carbonate	iron(III) bicarbonate
13	CuHSO4	copper(I) hydrogen sulfate	copper(I) bisulfate
14	Cu(H2PO3)2	copper(II) dihydrogen phosphite	copper(II) dihydrogen phosphite
15	Sn(HPO4)2	tin(IV) hydrogen phosphate	xxxxxxxxxxxxxxxxxx
16	Sb2(HPO3)3	antimony(III) hydrogen phosphite	xxxxxxxxxxxxxxxxxx