General Chemistry for the Health Care Professions

General Chemistry
for the
Health Care Professions

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1-14. NAMING BINARY ACIDS

All acids have hydrogen as the only cation. Binary acids are those acids that are composed of only two elements; that is, they consist of hydrogen in combination with some elemental anion. Usually the anion is a halide (F, Cl, Br, I), but binary acids with other anions also occur.

The names for the binary acids are formed by using the prefix hydro-, the root name for the anion, and the suffix -ic, followed by the word acid. For example, HCl is called hydrochloric acid.
An exception to this rule is hydrocyanic acid which has the formula HCN. Although this is a ternary acid, the cyanide radical (CN^-1) is usually treated like a halide ion when naming its compounds.
The binary acids are really covalent compounds which act as acids only when they are in solution, especially in water. When you know that one of the binary acids is by itself, you can properly name it in a similar manner to the salts; thus, HCl as a pure gas would be called hydrogen chloride.

Examples

HBr is hydrobromic acid

HI is hydriodic acid

H₂S is hydrosulfuric acid

HF gas is called hydrogen fluoride

1-15. NAMING TERNARY ACIDS

The ternary acids generally are made of hydrogen ion combined with one of the radicals that contain oxygen. F or this reason, they are often referred to as "oxyacids."

When naming the ternary acids, the suffixes on the names of the radicals are changed and followed by the word "acid" to show the presence of the hydrogen. Radicals ending in -ate change their suffix to -ic; radicals ending in -ite change their suffix to -ous. The prefixes, if there are any, are not changed. Occasionally, an extra syllable is added in the middle of the name for pronunciation purposes--these do not follow any pattern and must be learned. Here are some examples of naming ternary acids from the radicals:

RADICAL	NAME OF RADICAL	ACID	NAME OF ACID
SO₄^-2	Sulfate	H₂SO₄	Sulfuric acid
SO₃^-2	Sulfite	H₂SO₃	Sulfurous acid
ClO^-1	Hypochlorite	HClO	Hypochlorous acid

Examples

HNO₃ is called nitric acid

HNO₂ is called nitrous acid

HClO₄ is called perchloric acid

H₂CO₃ is called carbonic acid

H₃PO₃ is called phosphorous acid

H₃PO₄ is called phosphoric acid

Original content of this course is supplied by Academy of Health Sciences
Fort Sam Houston, Tx.