Sec 2 Chem: Acids and Bases- The Chemistry of Reactions

In essence

Acids react with:

·         Bases to form a salt and water

-       Hydrochloric Acid + Sodium Hydroxide à Sodium Chloride + Water

-       HCl + NaOH à NaCl + H₂O

·         Carbonates to form a salt, carbon dioxide and water

-       Hydrochloric Acids + Potassium Carbonate à Carbon Dioxide + Water + Potassium Chloride

-       HCl + K₂CO₃ à CO₂ + H₂O + 2KCl

·         Metals to form a salt and Hydrogen gas

-       Sulfuric acid + Magnesium à Hydrogen Gas + Magnesium Sulfate

-       H₂SO₄ + Mg à H2 + MgSO₄

·         Sulfites to form a salt, Sulfur Dioxide and Water

-       Sulfuric Acid + Magnesium Sulfite à Sulfur Dioxide + Water + Magnesium Sulfate

-       H₂SO₄ + MgSO₄ à SO₂ + H₂O + MgSO₄

Reaction of Bases: Note that Ammonia (NH3) and oxides of metals are bases too.

Bases react with:

·         Acids to form a salt and water

-       No need example, eh? Its same as above…

·         Ammonium salts (Salts with the NH₄ component) to form another salt, Ammonia gas and Water

-       Sodium Hydroxide + Ammonium Chloride à Ammonia + Water + Sodium Chloride

-       NaOH + NH₄Cl à NH₃ + H₂O + NaCl

·         Certain salt solutions (Non- Group I or Ammonium) to form an insoluble hydroxide* and another salt

-       Potassium Hydroxide + Copper (II) Sulfate à Potassium Sulfate + Copper (II) Hydroxide

-       2KOH + CuSO₄ à K₂SO₄ + Cu(OH)₂

You may wish to know what so special about the hydroxide, or about Grp I and ammonium salts. Refer to the post “Solubility rules”, in future….

*Types of Oxides

Oxides of Non-metals are either acidic or neutral Oxides of metals are usually basic and oxides of lead, zinc and aluminum are amphoteric. This means that they can act as BOTH acids and bases in reactions, depending on what it is reacted with.

Acidic Oxides	Basic Oxides	Amphoteric Oxides	Neutral Oxides
Carbon Dioxide	Cupper (II) Oxide	Beryllium	Carbon Monoxide
Sulfur Dioxide	Sodium Oxide	Tin	Nitrogen Monoxide
Nitrogen Dioxide	Iron (II) Oxide	Zinc
	Iron (III) Oxide	Lead
	Magnesium Oxide	Aluminum

Reactions of Amphoteric Oxides:

As a base, reaction with acids:

Zinc Oxide + Hydrochloric Acid à Water + Zinc Chloride

ZnO+ 2HCl à H₂O + ZnCl₂

As an acid, with bases:

Zinc Oxide + Sodium Hydroxide + Water (I Dunno what’s the water doing here)à Sodium Zincate

ZnO + 2NaOH + H₂O à Na₂ Zn(OH)₄