Acids & Bases 2Chapter 28

Objectives1.Outline of common laboratory acids and bases2.Be able to name some common lab acids and

bases3.Examine how acids and bases react in a

neutralisation reaction4.To look at some examples of neutralisation in

everyday life.5.To examine how salts are formed6.To study a simple neutralisation reaction

Properties of acids and bases:1.They affect the colour of indicators2.Bases which dissolve in water are called alkalis3.The pH scale gives an indication of the level of

acidity or basicity of a solution

Common lab acids and bases Acids: Hydrochloric Acid HCl

Sulfuric Acid H2SO4

Safety Symbols: CorrosiveKeep acids away from skin, eyes etc.

Bases: Sodium Hydroxide NaOH (commonly called caustic soda)

Used to clear blocked drainsSafety Symbol: Corrosive

Calcium Hydroxide Ca(OH)2

A solution of Calcium Hydroxide in water is called limewater.

Limewater is the chemical used to test for the presence of carbon dioxide in air. (lime water turns milky if CO2

Present)

Reaction of Acid + Base = neutralisation

Antacid = against acidAntacid is often written on medicineFor people with indigestion Problems.If a person has too much HCl acid in their

stomach they have indigestion if they take an antacid tablet it neutralise the acid and the indigestion goes away.

Examples of neutralisation in everyday life1.Toothpaste (a base) neutralises the acid on

your teeth.2.Baking soda (base) neutralises a bee sting

(acid)3.Vinegar (acid) neutralises a wasp sting (base)

Remember:Vinegar for vasp stings

Formation of SaltsWhen acid plus base neutralise each other you get:

Acid + Base = Salt + water

What is a salt?A salt is formed when the hydrogen in an acid is

replaced by a metal