Naming Acids and Bases Worksheet/Notes
Chemistry
2 points
Name: ________________________
Date: _____________ Hour: _______
According to Arrhenius’s definition, all acids produce H+ ions when dissolved in water.
Because of this, the formulas of most acids contain hydrogen. In fact, most acid formulas start with
hydrogen.
How can you tell just by looking at a chemical’s formula that it is an acid? __________________
______________________________________________________________________________
There are two types of acids: binary acids and oxyacids. Binary acids contain only two
elements, hydrogen and a nonmetal. Another way to think about it is that the anion of a binary acid
contains a nonmetal. Oxyacids contain more than two elements, and two of the elements are
hydrogen and oxygen. Another way to think about oxyacids is that they contain hydrogen and a
polyatomic anion.
What is a binary acid? ____________________________________________________________
______________________________________________________________________________
Below are the formulas of several acids. Circle the binary acids. Put a square around the oxyacids.
HCl
H2S
HMnO4
NaOH
HC2H3O2
HF
Sr(OH)2
H2SO4
H3N
Binary acids have a very simple naming system. Every binary acid’s name starts with hydroand ends with -ic acid. The rest of the name is taken from the anion’s name. For example, HBr’s
anion is Br- or bromide. The -ide is dropped, so just the brom- part is used. The name of HBr is then
hydrobromic acid.
Fill in the following chart about naming binary acids (may need ion chart):
Formula
Anion
Name of Anion
Name of Acid
ex> HBr
Br-
bromide
hydrobromic acid
HF
H3N
HI
How can the formula of a binary acid be written from just the name? Remember that all
charges in a compound must add to zero. If you know the charge of the anion, you can add enough
positive hydrogen ions to the beginning of the compound’s formula to cancel out the negatives. For
example, in hydrobromic acid, I know the bromide ion is present. Bromide has a 1- charge. I would
need one hydrogen ion to cancel out the bromide, so the formula for hydrobromic acid is HBr.
What would the formulas of the following acids be (may need ion chart)?
(a)
hydrochloric acid: __________________
(c)
hydroselenic acid: _______________
(b)
hydrophosphoric acid: _______________
(d)
hydrosulfuric acid: ______________
Oxyacids are slightly more difficult to name. Their names are still based on the anion
present, though. If an anion starts with per- and ends in -ate, the acid will be per-______-ic acid.
If the anion just ends in -ate (and DOESN’T start with per-), the acid will be ______-ic acid. If the
anion starts with hypo- and ends in -ite, the acid will be hypo-______-ous acid. If the anion ends
in -ite and DOESN’T start with hypo-, the acid will be ______-ous acid. For example, the acid
HMnO4 contains the MnO4- (permanganate) ion. It is called permanganic acid; the -ate part of the
ion’s name is dropped (just like the -ide part was dropped with binary acids).
Some students find putting these naming rules in a chart form helpful:
Name of ion
Name of acid
per_____ate
per_____ic acid
_____ate
_____ic acid
_____ite
_____ous acid
hypo_____ite
hypo_____ous acid
_____ide
hydro_____ic acid
Fill in the following chart about naming oxyacids (using your ion chart):
Formula
Anion
Name of Anion
Name of Acid
ex> HMnO4
MnO4-
permanganate
permanganic acid
HNO3
H2SO3
HClO
HIO4
Writing the formula of an oxyacid from its name is very similar to the process with binary
acids. In the name, look for any prefixes and suffixes. If you see per-, you know the anion will start
with per-; if you see -ic acid and no per-, you know the anion will end in -ate. Go to the ion chart
and find the anion. Add enough hydrogens to the front of the formula to cancel out the negative
charge. For example, the formula for chromic acid would be H2CrO4. How did I do that? I saw -ic
acid on the end and knew the ion would end in -ate. I looked on my ion chart for something with
chromium in it that ended in -ate and found chromate, CrO42-. Since it had a 2- charge, I added 2 H+
ions to the front, making H2CrO4.
Write the formula of the following acids (using your ion chart):
(a) carbonic acid
_______________
(d) oxalic acid
_______________
(b) nitrous acid
_______________
(e) acetic acid
_______________
(f) phosphoric acid
_______________
(c) hypochlorous acid _______________