Chemistry: Acids and Alkalis Revision
Acids
Bases
Examples:
A Substance that when dissolved in water forms H+ Ions
Hydrochloric Acid - HCL
Nitric - HNO3
Sulphuric Acid - H2SO4
Ethanoic (Acetic) Acid - CH3COOH
Alkalis
Examples:
Caustic Soda (Sodium Hydroxide) - NaOH
Ammonium Hydroxide - NH4OH
Calcium Hydroxide - Ca(OH)2
Indicators
pH Scale
Acids - Less than 7
Alkalis - More than 7
Neutral - 7
Gradual Change
Instant Change
A soluble base
Substances that neutralise acids
Neutral
Universal Indicator
Methyl Red
Methyl Orange
Phenolphthalein
Litmus
Conduction
Both acids and alkalis conduct electricity because they form ions when dissolved in water (electrolytes).
A compound that when dissolved in water does not produce H+ or OH- Ions or produces equal amounts of both.
Reactions
Neutralisation Reaction
Acid + Alkali --> Water + Salt
Electrolysis of an acid
Hydrogen at Cathode
Other Compound at Anode
Titration
The testing for the concentration of an unknown acid or alkali
Key Formula:
Moles = Concentration x Volume
Apparatus:
Pipette
Burette
Conical Flask
Below 0 - Above 14
Acids = Colourless
Bases = Pink
A mix of Several Indicators inducing gradual colour change
Red = Less than 3 pH
Orange / Yellow = 3 - 6 pH
Green = 7 pH
Blue = 8 - 11 pH
Violet = Greater than 11 pH
Examples:
Water
Human blood