The document discusses Arrhenius's theory of acids and bases. It defines acids as hydrogen-containing compounds that yield hydrogen ions (H+) in solution, and bases as compounds that yield hydroxide ions (OH-) in solution. It provides examples of common acids like hydrochloric acid and sulfuric acid, as well as bases like sodium hydroxide. It classifies acids based on the number of ionizable hydrogens they contain as mono-, di-, or triprotic. The document also discusses the properties of acids and bases and their reactions in aqueous solutions.

1. Acid & Base
Lesson1: Arrhenius's theory of
ionization

2. • Revise the properties of acids and
bases
• Define acid and base according to
Arrhenius's theory of ionization.
Objectives:

3. “ Some Properties of Acids
 Produce H+ (as H3O+)
 Taste sour
 Corrode metals
 Electrolytes
 React with bases to form a salt and water
 pH is less than 7
 Turns blue litmus paper to red “Blue to Red A-CID”

4. Some Properties of Bases
 Produce OH- ions in water
 Taste bitter, chalky
 Are electrolytes
 Feel soapy, slippery
 React with acids to form salts and water
 pH greater than 7
 Turns red litmus paper to blue “Basic Blue”

5. How did Arrhenius define an acid and
a base?
Arrhenius Acids and Bases

6. According to Swedish chemist Arrhenius,
Acids are hydrogen-containing
compounds that yield hydrogen ions (H+)
in solution.
Bases are compounds that yield
hydroxide ions (OH–) in aqueous solution.
Arrhenius Acids and Bases

7. Arrhenius Acids
Some Common Acids
Name Formula
Hydrochloric acid HCl
Nitric acid HNO3
Sulfuric acid H2SO4
Phosphoric acid H3PO4
Ethanoic acid CH3COOH
Carbonic acid H2CO3
Acids vary in the number of hydrogens they
contain that can form hydrogen ions.
Arrhenius Acids

8. A hydrogen atom that can form a hydrogen
ion is described as ionizable.
• Nitric acid (HNO3) has one ionizable hydrogen.
Nitric acid is classified as a monoprotic
• acid.The prefix mono- means “one,” and the stem
protic reflects the fact that a hydrogen ion is a proton.
Arrhenius Acids

9. 1- MONOPROTIC ACID
• Acid that contain one ionizable hydrogen. (HNO3) Nitric
acid is classified as a monoprotic acid.
2- DIPROTIC ACIDS.
• Acids that contain two ionizable hydrogens, such as
sulfuric acid (H2SO4), are called diprotic acids.
3- TRIPROTIC ACIDS.
• Acids that contain three ionizable hydrogens, such as
phosphoric acid (H3PO4), are called triprotic acids.
Arrhenius Acids

10. Not all compounds that contain hydrogen are
acids.
• Only a hydrogen that is bonded to a very
electronegative element can be released as
an ion. Such bonds are highly polar.
• When a compound that contains such bonds
dissolves in water, it releases hydrogen ions.
Arrhenius Acids

11. In an aqueous solution, hydrogen ions are
not present. Instead, the hydrogen ions are
joined to water molecules as hydronium ions.
• A hydronium ion (H3O+) is the ion that forms
when a water molecule gains a hydrogen ion.
Arrhenius Acids

12. Some Common Bases
Name Formula Solubility in Water
Sodium hydroxide NaOH High
Potassium hydroxide KOH High
Calcium hydroxide Ca(OH)2 Very low
Magnesium hydroxide Mg(OH)2 Very low
The table below lists four common bases.
Arrhenius Bases

13. The base sodium hydroxide
(NaOH) is known as lye.
• Sodium hydroxide is an ionic solid.
• It dissociates into sodium ions in aqueous
solution.
Arrhenius Bases

14. The base sodium hydroxide
(NaOH) is known as lye.
• Sodium hydroxide is extremely
caustic.
– A caustic substance can burn or eat away materials
with which it comes in contact.
– This property is the reason that sodium hydroxide is a
major component of products that are used to clean
clogged drains.
Arrhenius Bases

15. Sodium and potassium are Group 1A
elements. Elements in Group 1A, the alkali
metals, react violently with water.
• The products of these reactions are aqueous
solutions of a hydroxide and a hydrogen gas.
Arrhenius Bases

16. •Nitrogen compounds in
bat urine can
decompose and release
ammonia into the air.
Why are high levels of ammonia harmful
to you?
Ammonia is a base,
and bases are
caustic in high
concentrations.

17. Objective: To determine experimentally how acids and bases
react to litmus, a metal and phenolphthalein
Go to ACID&BASE ACTIVITY
Task : Acids and Bases identification
Lab