Section 2.4—Defining, Naming & Writing Acids & Bases We need to know what acids behave when talking about ant-acids!

Acids

Acids – Arrhenius Definition Produce Hydronium ion (H3O+1) in water Hydronium ion is water + a hydrogen cation H O water H O +1 H +1 By this definition, if an acid is to give a H+1 to water, then all acids will have hydrogen as the cation (first element written).

How do Acids produce Hydronium? - water acid Hydrogen cation with some anion

How do Acids produce Hydronium? - +1 H O

How do Acids produce Hydronium? - +1 H O Hydronium ion Anion

Naming Acids

Naming non-oxygen Acids These compounds have: Start with “H” (more than 1 “H” is OK, too). Do not contain oxygen To name these compounds: Use “hydro____ic acid” Fill in the blank with the anion’s name without the last syllable

Example #1 HBr

HBr Example #1 Hydrobromic acid Hydrogen cation Bromine It’s an acid No oxygen Use “hydro___ic”

Naming Oxygen Acids These compounds have: To name these compounds: Start with “H” (more than 1 “H” is OK, too). Do contain oxygen To name these compounds: Use “___ic acids” for “-ate” anions Use “___ous acids” for “-ite” anions Do not use “hydro” with these…the word “acid” is how you know it begins with hydrogen, not “hydro-”

Example #2 H2SO3

H2SO3 Example #2 Sulfurous acid Hydrogen cation Sulfite ion It’s an acid Hydrogen cation H2SO3 Sulfite ion “-ite” ion Use “___ous” acid Sulfurous acid

Example #3 H2SO4

H2SO4 Example #3 Sulfuric acid Hydrogen cation Sulfate ion It’s an acid Hydrogen cation H2SO4 Sulfate ion “-ate” ion Use “___ic” Sulfuric acid

Write the name for the following compounds Let’s Practice HCl HNO3 H2S H3PO3 Example: Write the name for the following compounds

Write the name for the following compounds Let’s Practice HCl HNO3 H2S H3PO3 Hydrochloric acid Nitric acid Hydrosulfuric acid Phosphorous acid Example: Write the name for the following compounds

Writing Acid Formulas

“Hydro-” acids To write these formulas: The cation is H+1 Write the anion and charge Balance the charges by adding the appropriate subscript to the hydrogen cation

Example #4 Hydrofluoric acid

Does not contain oxygen Example #4 H+1 Hydrogen cation Hydrofluoric acid Does not contain oxygen F-1

Does not contain oxygen Example #4 H+1 Hydrogen cation Hydrofluoric acid Does not contain oxygen H+1F-1 F-1 +1 + -1 = 0 HF The compound is neutral. Subscripts are not needed

NON “Hydro-” acids To write these formulas: The cation is H+1 If it is an “-ic” acid, the anion is the “-ate” polyatomic ion If it is an “-ous” acid, the anion is the “-ite” polyatomic ion Add subscript to the hydrogen cation to balance charges

Example #5 Carbonic acid

From the “___ate” anion Example #5 H+1 Hydrogen cation Carbonic acid From the “___ate” anion CO3-2

From the “___ate” anion Example #5 H+1 Hydrogen cation H+CO32- +1 + -2 = -1 Carbonic acid H+H+CO32- +1 + 1 + -2 = 0 From the “___ate” anion CO3-2 H2CO3

Example #6 Nitrous acid

From the “___ite” anion Example #6 H+1 Hydrogen cation Nitrous acid From the “___ite” anion NO3-1

From the “___ite” anion Example #6 H+1 Hydrogen cation Nitrous acid H+NO2- From the “___ite” anion +1 + -1 = 0 NO3-1 HNO2

Write the formula for the following acids Let’s Practice Phosphoric acid Hydroiodic acid Carbonous acid Perchloric acid Example: Write the formula for the following acids

Write the formula for the following acids Let’s Practice Phosphoric acid Hydroiodic acid Carbonous acid Perchloric acid H3PO4 HI H2CO2 HClO4 Example: Write the formula for the following acids

Bases

Bases – Arrhenius Definition Bases produce the hydroxide ion in water H O -1 Hydroxide Ion

Naming & Writing Bases

Naming Bases Most bases are just ionic compounds with “hydroxide” as their anion The most common exception to this is ammonia NH3 (ammonia) is a base even though it doesn’t contain “-OH” as the anion

Example #7 NaOH

Example #7 Sodium NaOH Sodium Hydroxide Hydroxide

Write the formula or name for each Let’s Practice Ca(OH)2 KOH Sr(OH)2 Copper (II) hydroxide Magnesium hydroxide Example: Write the formula or name for each

Write the formula or name for each Let’s Practice Ca(OH)2 KOH Sr(OH)2 Copper (II) hydroxide Magnesium hydroxide Calcium hydroxide Potassium hydroxide Strontium hydroxide Cu(OH)2 Mg(OH)2 Example: Write the formula or name for each