Acids, Bases, Salts

What is a salt

A salt is a substance formed when a metal ion replaces the H+ ions in an acid

What are the two parts of a salt

Metal: cation (comes from the base)

Non-metal or radicals: anion (comes from the acid)

What is an oxide

An oxide is a compound of Oxygen and another element through the process of Combustion

Nb. Metals form Metal Oxides and Non-Metals form Non-Metal Oxides

What can oxides be classified as

Acidic

Basic

Amphoteric

Neutral

What is the nature of the oxides of the elements across the periodic table from left to right

Basic —> Amphoteric —> Acidic

Acidic Oxides

1. Do not react with acids

2. React with bases and alkalis to form salt and water

3. Dissolve in water to form acidic solution

4. Gases at room temperature

Example: SO₂ , SO₃ , CO₂ , NO₂

Basic Oxides

1. Do not react with bases

2. React with acids to form salt and water

3. Usually insoluble in water. Those that dissolve in water form alkaline solutions

Examples: Na₂O , CaO , MgO , FeO , CuO

Neutral Oxides

1. Neutral pH

Examples: CO , NO , H₂O

Amphoteric Oxide

1. React with both acids and bases to form salt and water

Examples: ZnO , Al₂O₃ , PbO

(Oxides formed with metals near “STEPS”)

What is the pH scale

The pH scale is a scale of number from 0 to 14 which is used to show acidic or alkaline solutions

• A pH below 7 is acidic

• A pH above 7 is alkaline

• A pH of exactly 7 is neutral