Honors Chemistry                                                        Name______________________

Nomenclature Packet—PMP 3—Acid Nomenclature

Mr. McAfoos                                                               Period______ Date___________

 

There are two skills you must master, writing the formula of a compound when you are given the name, and writing the name of a compound when you are given the formula.

 

Acids are compounds made by adding H⁺¹ ions (or several H⁺¹ ’s) to a negative ion. The name of the acid depends on the name of the negative ion to which the H’s are attached. Therefore, naming an acid from its formula requires knowledge of ion names.  You must know the polyatomic ions to be able to name acids! In addition, any element that as a negative charge can be named as an ion. This is done by removing the ending of the element name and replacing it with “ide.” For example, oxygen becomes oxide, sulfur becomes sulfide. The charge on such an ion is ALWAYS the negative charge predicted by the electron configuration (add electrons to make it like a noble gas!).

 

Naming Formulas

There are three basic acid name forms, which correspond to three basic ion name forms.

Ion Name Ends in	Acid Name
"ATE "	"IC acid "
Example:    nitrate  (NO3-1 )	nitric acid (HNO3)
"ITE "	"OUS acid "
Example:  nitrite  (NO2-1 )	nitrous acid  (HNO2)
"IDE "	"HYDRO..IC acid "
Example: chloride (Cl-1 )	Hydrochloric acid

 

A few ions (sulfate, sulfite, phosphate) are lengthened in the acid name to sound better.  So, sulfate makes sulfuric acid not sulfic acid.

 

Formula Writing

When given the name of an acid, first use the chart above to determine what the name of the ion was. Then write that ion. One H is needed for each negative charge (so SO₄^-2 needs 2 H’s).

 

            Example 1: Chromic acid…ic comes from ate…so…chromate is the ion

            Then CrO₄^-2 needs 2 H’s

            So…H₂CrO₄

            Example 2: Hypobromous acid…ous comes from ite…so…hypobromite is the ion

            BrO^-1 needs 1 H

            So…HBrO

Example 3: Hydroiodic acid…hydro__ic comes from ide…so…iodide is the ion.

            Iodide is iodine with a negative charge (-1 since it’s one away from being like Xe)

            So…I^-1 needs 1 H…so…HI

Name the following acids:

1) H₃PO₄

 

2) H₂CO₃

 

3) H₂SO₄

 

4) HIO₃

 

5) HF

 

6) HNO₂

 

Write the formula for these acids:

7) hydrobromic acid

 

8) hydrocyanic acid

 

9) nitric acid

 

10) sulfurous acid

 

11) phosphorous acid

 

12) acetic acid