Properties of Acids and Bases

Section 6.1-6.2

Properties of Acids and Bases Acids and Bases can both be defined ________________ and

____________________.

You are expected to be able to provide any of the following definitions and use them to answer questions.

Empirical Definitions

Acid – a substance which dissolves in water to produce a solution that:

Base – a substance which dissolves in water to produce a solution that:

Theoretical Definitions

a) Arrhenius:

Acid – a substance that forms an acidic solution by dissolving in water to produce free hydrogen ions (H+

(aq)) in solution

Base – a substance that forms a basic solution by dissolving in water to produce free hydroxide ions (OH-

(aq)) in solution

Theoretical Definitions

b) Modified Definition:

Acid – a species that forms an acidic solution by reacting with water to produce hydronium ions (H3O+

(aq))

Base – a species that forms a basic solution by reacting with water to produce hydroxide ions (OH-

(aq))

The hydronium ion (hydrated proton) – was discovered by Paul Giguère at the Université Laval in 1957.

The Hydronium Ion

Theoretical chemists thought it was unlikely that a ___________________, which is a tiny

proton with a very high charge-to-size

ratio, could exist on its own in aqueous solution.

Instead they thought it would bond strongly to polar water molecules.

Paul Giguère provided empirical evidence for this type of bonding when he

discovered hydrated protons (H3O+(aq)); commonly called hydronium ions

The modern view of acids and bases is that the hydronium ions (H3O+(aq)); are

responsible for acidic properties and hydroxide ions (OH–(aq)) are

responsible for basic properties

Learning Tips: The terms “acid” and “base” refer to chemical

substances, whereas the terms “acidic” and “basic” refer to the properties of a solution

Chemists have known about some acids for hundreds of years. Because these acids are commonly known by familiar names, their IUPAC names are not often used. You should know both forms of naming for acids.

Do you remember how to name acids?

Naming Acids

Systematic IUPAC

1) aqueous hydrogen chloride

2) aqueous hydrogen chlorate

3) aqueous hydrogen chlorite

Traditional Classical

1) hydrogen ______ide = hydro______ic acid

2) hydrogen ______ate = __________ic acid

3) hydrogen ______ite = __________ous acid

Remember: acid contains sulfur = you add a ur H2SO4(aq) sulfuric acid acid contains phosphorus = add an or H3PO4(aq) phorphoric acid

Practice – Naming Acids

IUPAC

HClO4(aq)

HClO(aq)

HNO2(aq)

HNO3(aq)

H2SO4(aq)

H2SO3(aq)

H3PO4(aq)

Traditional

Homework

Read pg. 234-237

Do pg. 237 #3