Remember that the names of Arrhenius acids usually end in acid (hydrochloric acid, sulfuric
acid, nitric acid ) and that their formulas fit one of two general patterns:
HX(aq) X = F, Cl, Br, or I
For example, HCl(aq) (hydrochloric acid), H2SO4,
(sulfuric acid), and HNO3 (nitric acid) represent acids.
Names and Formulas for Binary Acids
Binary acids are named by writing hydro followed by the root of the name of the halogen, then -ic,
and finally acid:
The only exception to remember is that the “o” in hydro is left off for HI(aq), so its name is hydriodic acid
(an acid used to make pharmaceuticals).
Most chemists refer to pure HCl gas as hydrogen chloride, but when HCl gas is dissolved in water, HCl(aq),
the solution is called hydrochloric acid. We will follow the same rule in this
text, calling HCl or HCl(g) hydrogen chloride and calling HCl(aq) hydrochloric
acid. The same pattern holds for the other binary acids as well.
You will be
expected to be able to write formulas and names for the binary acids found
below . Remember that it is a good habit to write (aq)
after the formula.
HF(aq) - hydrofluoric acid
HCl(aq) - hydrochloric acid
HBr(aq) - hydrobromic acid
HI(aq) - hydriodic acid
H2S(aq) - hydrosulfuric acid
HF - hydrogen fluoride or hydrogen monofluoride
HCl - hydrogen chloride or
HBr - hydrogen bromide or
HI - hydrogen iodide or hydrogen moniodide
H2S - hydrogen sulfide or dihydrogen monosulfide
Names and Formulas for Oxyacids
To name oxyacids, you must
first be able to recognize them by the general formula HaXbOc,
with X representing an element other than hydrogen or oxygen. It will also be
useful for you to know the names of the polyatomic oxyanions, because many
oxyacid names are derived from them. If enough H+ ions are added to a
(root)ate polyatomic ion to completely neutralize its charge, the (root)ic acid
(See below. ).
- If one H+ ion is
added to nitrate, NO3-,
nitric acid, HNO3,
- If two H+ ions
are added to sulfate, SO42-,
sulfuric acid, H2SO4,
- If three H+ ions
are added to phosphate, PO43-,
phosphoric acid, H3PO4,
Notice that the
whole name for sulfur, not just the root, sulf‑, is found in the name
sulfuric acid. Similarly, although the usual root for phosphorus is phosph-,
the root phosphor‑ is used for phosphorus-containing oxyacids, as in the
name phosphoric acid.
is nitrate, and HNO3 is nitric acid.
is acetate, and HC2H3O2 is acetic acid.
is sulfate, and H2SO4 is sulfuric acid.
is carbonate, and H2CO3 is carbonic acid.
is phosphate, and H3PO4 is phosphoric acid.