Acids

1
Acids and Bases Definitions

• Acids
• taste sour
• turn litmus red
• react with active metals to release hydrogen gas
• react with bases to form water and a salt
• Bases
• taste bitter
• turn litmus blue
• feel slippery
• react with acids to form water and a salt
• Salt - an ionic compound

2
Acids, Bases, and Salts - Arrhenius Theory

• Acid a molecular substance that ionizes in
  aqueous solution to form hydrogen ions (H)
• Base a substance that produces hydroxide ions
  (OH-) in aqueous solution

3
Acids, Bases, and Salts

• Limitations of the Arrhenius Theory
• H ions do not exist in water solution. Protons
  react with water to form hydronium ions. (H3O)
• H H2O ? H3O
• The Arrhenius Theory does not explain the
  basicity of ammonia and similar compounds.
• It only applies to reactions in aqueous solution.

4
Acids, Bases, and Salts

• Brønsted-Lowry Theory
• Acid proton donor
• HA H2O ? H3O A-
• Base proton acceptor
• NH3 H2O ? NH4 OH-

5
Strong and Weak Acids Bases

• Strong acids ionize completely in water solution
  (100)
• HCl(aq) ? H(aq) Cl-(aq)
• Weak acids only partially ionize in water
  solution ltlt 100
• HCN(aq) ? H(aq) CN-(aq)
• Strong bases ionize completely in water solution
  (100)
• NaOH(aq) ? Na(aq) OH-(aq)
• Weak bases only partially ionize in water
  solution ltlt 100
• NH3(aq) H2O ? NH4(aq) OH-(aq)

6
Strong and Weak Acids Bases
MEMORIZE!!!
7
Neutralization

• The reaction of an acid with a base is called
  neutralization. Water molecules are the result
  of the reaction between hydrogen ions and
  hydroxide ions.
• H OH- ? H2O
• During neutralization, an acid reacts with a
  base, forming water and a salt.

8
Acids, Bases, and Salts - Chemical Reactions!

• Neutralization When an acid reacts with a base,
  the properties of each are neutralized and the
  products are water and a salt.
• Acid Base ? Water Salt
• The amount of acid (or base) in a solution is
  determined by careful neutralization

9
The pH Scale

• pH is a means of expressing the acidity or
  basicity of a solution
• pH means power of hydrogen.
• pH -logH

10
The pH Scale
11
Acid Rain

• Nonmetal oxides present in air react with water,
  forming acidic solutions. Rain with a pH of less
  than 5.6 is considered to be acid rain. Carbon
  dioxide (CO2), sulfur dioxide (SO2), nitrogen
  monoxide (NO), and nitrogen dioxide (NO2) are the
  major nonmetallic oxides responsible for acid
  rain formation.

12
Antacids A Basic Remedy

• Hyperacidity is when the stomach secretes too
  much acid. Antacids are often taken to
  neutralize excess acid and reduce the symptoms of
  hyperacidity.
• Excessive use of antacids can lead to an
  increase in the pH of blood, a condition known as
  alkalosis.

13
Antacids A Basic Remedy
14
Acids Bases in Industry and at Home

• Sulfuric acid is the leading chemical substance
  produced in the U.S. It is used to manufacture
  fertilizers and industrial chemicals. It is the
  acid of automotive batteries. Production is 40
  billion kg/year.
• Hydrochloric acid has a number of uses. It is
  used as a rust remover, it removes lime from
  mortar and household plumbing fixtures. It can
  be purchased from hardware stores as muriatic
  acid. Annual U.S. production is 4 billion kg.

15
Acids Bases in Industry and at Home

• Lime (CaO) is produced by heating limestone
  (CaCO3).
• CaCO3 heat ? CaO CO2
• Lime can be slaked by reacting with water to
  make calcium hydroxide (Ca(OH)2). Slaked lime is
  used to make mortar and cement and to sweeten
  soil. Annual U.S. production is 22 billion kg.
• Soil can be sweetened by adding slaked lime
  Ca(OH)2.

16
Acids Bases in Industry and at Home

• Sodium hydroxide, also known as lye, can be
  purchased for home use as oven cleaner or drain
  cleaners. It is used commercially to make soap.
  Annual U.S. production is 9 billion kg.
• Ammonia is produced for use as fertilizer and in
  household cleaning products. Production is about
  11 billion kg/year.

17
Acids Bases in Health and Disease

• Concentrated acids and bases are corrosive to
  tissue and are health hazards. They can denature
  proteins in living cells.
• The human body has wonderful mechanisms for
  maintaining the proper pH of tissue, blood, and
  body fluids.