Section 2.8

Naming Simple Compounds

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What is an Acid?

• There are many different definitions of an acid. We will be working with the simplest definition.

• ACID – is a H+ (hydronium ion) donor.

• This means that our acids will begin with the element “H”

Section 2.8

Naming Simple Compounds

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2

• Acids can be recognized by the hydrogen that appears first in the formula—HCl.

• Molecule with one or more H+ ions attached to an anion.

Acids

Section 2.8

Naming Simple Compounds

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Naming Acids

• All acids are named by FIRST identifying the ANION present

• Ignore the NUMBER of “H” atoms in the formula – concentrate on identifying the anion.

Section 2.8

Naming Simple Compounds

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Naming Acids

There are only three rules to remember

Anion Name Acid Name

- ide Hydro- -ic Acid

-ate -ic Acid

-ite -ous Acid

Section 2.8

Naming Simple Compounds

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Try a Few

Acid Anion Acid Name

HCl Cl- Chloride Hydrochloric Acid

H3PO4 PO43- Phosphate Phosphoric Acid

H2SO3 SO32- Sulfite Sulfurous Acid

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Naming Simple Compounds

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• If the anion does not contain oxygen, the acid is named with the prefix hydro– and the suffix –ic.

Examples:

HCl Hydrochloric acid

HCN Hydrocyanic acid

H2S Hydrosulfuric acid

Acids - review

Section 2.8

Naming Simple Compounds

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7

Acids That Do Not Contain Oxygen

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Naming Simple Compounds

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The suffix –ic is added to the root name if the anion name ends in –ate.•Examples:

HNO3 Nitric acid

H2SO4 Sulfuric acid

HC2H3O2 Acetic acid

The suffix –ous is added to the root name if the anion name ends in –ite.•Examples:

HNO2 Nitrous acid

H2SO3 Sulfurous acid

HClO2 Chlorous acid

Rules for Naming Acids – if the anion contains oxygen

Section 2.8

Naming Simple Compounds

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Naming Acids

• The rules don’t change just because the anion has a prefix

Anion Name Acid Name• perchlorate perchloric acid

• hyponitrite hyponitrous acid

Section 2.8

Naming Simple Compounds

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Naming Acids- Examples

Acid Anion Acid Name

HClO ClO- HypoChlorite Hypochlorous Acid

H3PO5 PO53- PerPhosphate Perphosphoric Acid

• The –ate and –ite ending of the anion still dictate how the acid will be named

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Naming Simple Compounds

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11

Flowchart for Naming Acids

Section 2.8

Naming Simple Compounds

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Writing Acids

This process is just the opposite of naming.

1. Identify the anion

2. Write the anion (including its charge)

3. The charge on the anion tell you how many “H+” atoms to add

4. Remove all charges

Section 2.8

Naming Simple Compounds

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Writing Acids

Name Anion Acid FormulaHydrobromic acid Br- HBr

Sulfuric acid SO42- H2SO4

Periodic acid IO4- HIO4

Phosphorous acid PO33- H3PO3

Section 2.8

Naming Simple Compounds

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14

Flowchart for Naming Acids