Chemistry Reference
In-Depth Information
8. What would be the pH value of a solution with a [H
3
O
+
] of 5.9 × 10
-3
?
9. What would be the pH value of a solution with a [OH
-
] of 3.5 × 10
-5
?
10. What would be the H
3
O
+
concentration of a solution with a pH of 5?
Lesson 9-3: Naming Acids
By now, you have probably noticed that the rules for naming acids seem
to differ from the rules for naming other compounds. Perhaps you have
heard your instructor refer to the compound with the formula HCl as “hy-
drochloric acid,” but, according to the rules for naming compounds that
we went over in Lesson 5-3, it should be called “hydrogen chloride.” Fol-
lowing the rules from Lesson 5-3, the compound with the formula H
2
SO
4
should be named “hydrogen sulfate,” but you may have seen it referred to
as “sulfuric acid.” What is going on here? Are there special rules for nam-
ing acids? The answer is yes!
When a compound dissolves in water to form an acidic aqueous solu-
tion, it gets a special “acid” name. Fortunately, it is quite easy to derive the
common names of these acids. I can summarize what you need to know in
three easy rules.
1.
If the acid is a binary compound, as in HCl, shorten the “hydrogen” to
“hydro” and change the ending from “ide” to “ic.” Then add the word
acid at the end.
Naming the Acid With the Formula HCl
Hydrogen Chloride + ic + “acid” becomes Hydrochloric Acid
Following this rule, H
2
S becomes “hydrosulfuric acid” and HI be-
comes “hydroiodic acid.” Look at how the names change in the follow-
ing table, and only move on to the next rule when you are sure that you
see the pattern.
Names of the Binary Acids
Formula
Name of Solid Compound
Name of Acid in Solution
HBr
Hydrogen bromide
Hydrobromic acid
HCl
Hydrogen chloride
Hydrochloric acid
HF
Hydrogen fluoride
Hydrofluoric acid
HI
Hydrogen iodide
Hydroiodic acid
H
2
S
Hydrogen sulfide
Hydrosulfuric acid
