Chemical Nomenclature 4:
The Names and Chemical Formulas of the Oxyacids
A: The Seven Common Oxyacids
As their name implies the oxyacids contain the element oxygen. However, the hydrogen atom(s) in
the oxyacids give the molecule its acid character. Since these compounds behave as acids only
when dissolved in water the abbreviation (aq) is added to complete the chemical formula.
Table 1: The Seven Common “-ic” Oxyacids
NAME
FORMULA
chloric acid
HClO3 (aq)
bromic acid
HBrO3 (aq)
iodic acid
HIO3 (aq)
nitric acid
HNO3 (aq)
carbonic acid
H2CO3 (aq)
sulphuric acid
H2SO4 (aq)
phosphoric acid
H3PO4 (aq)
These seven names and formulas will be used as the starting point for the nomenclature of the
oxyacids. Note that the numbers of hydrogen and oxygen atoms are specific to each oxyacid.
Memorize the names and formulas of these seven oxyacids. Successful memorization is indicated
by reciting Table 1 twice without error or hesitation to your partner. After you have successfully
recited the names and formulas of these seven oxyacids complete Table 2 from memory.
Table 2: The Seven Common “-ic” Oxyacids
NAME
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FORMULA
1
B: The Oxyacid Families
Different oxyacids can be made by adding or reducing the number of oxygen atoms in the formulas
and then re-naming the acid accordingly. There are only three variations that will be considered
here. These variations apply to all of the acids listed above, but will be illustrated by example with
chloric acid, HClO3 (aq).
1 Adding one oxygen atom to the formula of chloric acid (HClO3) changes the formula to HClO4.
The name of the acid is altered by adding the prefix "per". The name of HClO4 (aq) is perchloric
acid.
2 Removing one oxygen atom from the formula of chloric acid changes the formula to HClO2.
The name is altered by replacing the "-ic" suffix with "-ous". The name of HClO2 (aq) is
chlorous acid.
3 Removing two oxygen atoms from the formula of chloric acid changes the formula to HClO.
The name is changed by adding the prefix "hypo-" and replacing the "-ic" suffix with "-ous". The
name of HClO (aq) is hypochlorous acid.
Begin by completing the names and formulas of the seven oxyacids in column #3 to Table 3 below.
Use the three rules stated above to complete each cell of Table 3. Write the appropriate name if the
formula is given or enter the chemical formula where the name is given. Check your work against
the answers provided in Table 4.
Table 3: Nomenclature of the Seven Oxyacids
hypo-_______-ous
acid
_______-ous acid
_______-ic acid
per-_______-ic acid
HClO4 (aq)
chlorous acid
HClO3 (aq)
chloric acid
HClO (aq)
HBrO2 (aq)
HBrO4 (aq)
hypobromous acid
bromic acid
HIO (aq)
HIO3 (aq)
iodous acid
periodic acid
HNO2 (aq)
HNO4 (aq)
hyponitrous acid
nitric acid
H2CO (aq)
H2CO3 (aq)
carbonous acid
percarbonic acid
H2SO3 (aq)
H2SO5 (aq)
hyposulphurous acid
sulphuric acid
H3PO2 (aq)
H3PO4(aq)
phosphorous acid
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perphosphoric acid
2
Table 4: Complete Nomenclature of the Seven Oxyacids
hypo-_______-ous
_______-ous acid
_______-ic acid
per-_______-ic acid
HClO (aq)
hypochlorous acid
HClO2 (aq)
chlorous acid
HClO3 (aq)
chloric acid
HClO4 (aq)
perchloric acid
HBrO (aq)
hypobromous acid
HBrO2 (aq)
bromous acid
HBrO3 (aq)
bromic acid
HBrO4 (aq)
perbromic acid
HIO (aq)
hypoiodous acid
HIO2 (aq)
iodous acid
HIO3 (aq)
iodic acid
HIO4(aq)
periodic acid
HNO (aq)
hyponitrous acid
HNO2 (aq)
nitrous acid
HNO3 (aq)
nitric acid
HNO4(aq)
pernitric acid
H2CO (aq)
hypocarbonous acid
H2CO2 (aq)
carbonous acid
H2CO3 (aq)
carbonic acid
H2CO4 (aq)
percarbonic acid
H2SO2 (aq)
hyposulphurous acid
H2SO3 (aq)
sulphurous acid
H2SO4 (aq)
sulphuric acid
H2SO5 (aq)
persulphuric acid
H3PO2 (aq)
hypophosphorous acid
H3PO3 (aq)
phosphorous acid
H3PO4 (aq)
phosphoric acid
H3PO5 (aq)
perphosphoric acid
acid
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1.
Write the names of the oxyacids represented by the following formulas.
FORMULA
2.
NAME
FORMULA
H2SO4 (aq)
HNO2 (aq)
HIO2 (aq)
H2CO (aq)
H3PO3(aq)
HBrO2 (aq)
HClO2 (aq)
H3PO5 (aq)
HClO4 (aq)
HNO (aq)
H2SO3 (aq)
HNO4 (aq)
H2CO3 (aq)
HIO3 (aq)
HBrO4 (aq)
HbrO (aq)
H3PO2 (aq)
H2SO2 (aq)
HNO3 (aq)
HIO4 (aq)
HIO (aq)
HClO (aq)
H3PO4 (aq)
H2CO3(aq)
H2CO4 (aq)
HClO3 (aq)
NAME
Write the formulas of the oxyacids represented by the following names.
NAME
FORMULA
NAME
perphosphoric acid
chlorous acid
nitrous acid
sulphuric acid
hypocarbonous acid
iodous acid
bromous acid
phosphorous acid
nitrous acid
perchloric acid
pernitric acid
sulphurous acid
iodic acid
carbonic acid
hypobromous acid
perbromic acid
hyposulphurous acid
hypophosphorous acid
chloric acid
percarbonic acid
phosphoric acid
hypochlorous acid
carbonous acid
hydrosulphuric acid
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4
FORMULA