1. SCH3U/4C Ms. Richardson Chemistry in the Environment
ACIDS & BASES
SCH3U/4C Ms. Richardson
Chemistry in the Environment

2. Common industrial acids & Bases
Hydrochloric acid (HCl) – textiles, photography, food, rubber industries; mining
Ammonia (NH3) – fertilizer, synthetic fibres, commercial explosives
Phosphoric acid (H3PO4) – soft drinks, detergents, dentistry
Lime (CaO) – agriculture, construction, scrubber technology
Sulfuric acid (H2SO4) – electrolytes, medicines, explosives, dyes/paints, soaps; mining
Sodium hydroxide (NaOH) – drain cleaner, soaps, plastic; oil refining, fracking

3. Properties of Acids And Bases
Conduct the lab and summarise the properties of acids and bases.

4. Theories of Acids & Bases
The Arrhenius Theory describes acids and bases based on how they behave in water.
Acids ionize in water to produce one or more hydrogen ions.
HCl(g)  H+(aq) + Cl -(aq)
Bases dissociate in water to release one or more hydroxide ions.
NaOH(g)  Na+(aq) + OH -(aq)

5. Problems with The Arrhenius Theory
Arrhenius’ theory doesn’t work for all acids and bases.
Consider ammonia, NH3 which doesn’t contain hydroxide but forms basic solutions when dissolved in water.
NH3(g) + H2O(l) NH4+(aq) + OH-(aq)

6. Problems with Arrhenius Theory
When acids ionize, the H+(aq) that form are attracted to water and react with the water to form H3O+(aq), known as the hydronium ion.
H+(aq) + H2O(l)  H3O+ (aq)

7. The Modified Arrhenius Theory
ACID: A substance that reacts with water to produce H3O+(aq) in aqueous solution.
BASE: A substance that dissociates in water or reacts with water to produce OH-(aq) in aqueous solution.