Chemistry Notes
Chapter: Acid-Base Reactions
Topic: Acids, Bases, and pH
1. Introduction to Acids and Bases
Acids are substances that donate protons (H⁺ ions) in a reaction.
Bases are substances that accept protons (H⁺ ions) or donate hydroxide ions (OH⁻) in a
reaction.
Examples:
Acids: Hydrochloric acid (HCl), Sulfuric acid (H₂SO₄), Nitric acid (HNO₃).
Bases: Sodium hydroxide (NaOH), Ammonia (NH₃), Calcium hydroxide (Ca(OH)₂).
2. Theories of Acids and Bases
Several theories explain the behavior of acids and bases. The most common are:
2.1. Arrhenius Theory
Acid: A substance that increases the concentration of H⁺ ions in aqueous solution.
Base: A substance that increases the concentration of OH⁻ ions in aqueous solution.
Example:
HCl→H++Cl−\text{HCl} \rightarrow \text{H}^+ + \text{Cl}^-HCl→H++Cl− (Acid)
NaOH→Na++OH−\text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^-NaOH→Na++OH− (Base)
2.2. Bronsted-Lowry Theory
Acid: A proton (H⁺) donor.
Base: A proton (H⁺) acceptor.
Example:
In the reaction between HCl and water: HCl+H2O→H3O++Cl−\text{HCl} +
\text{H}_2\text{O} \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^-HCl+H2O→H3O++Cl− Here,
HCl donates a proton (H⁺), acting as an acid, and water acts as a base by accepting the
proton.
2.3. Lewis Theory
Acid: A substance that can accept a pair of electrons.
Base: A substance that can donate a pair of electrons.
Example:
Chapter: Acid-Base Reactions
Topic: Acids, Bases, and pH
1. Introduction to Acids and Bases
Acids are substances that donate protons (H⁺ ions) in a reaction.
Bases are substances that accept protons (H⁺ ions) or donate hydroxide ions (OH⁻) in a
reaction.
Examples:
Acids: Hydrochloric acid (HCl), Sulfuric acid (H₂SO₄), Nitric acid (HNO₃).
Bases: Sodium hydroxide (NaOH), Ammonia (NH₃), Calcium hydroxide (Ca(OH)₂).
2. Theories of Acids and Bases
Several theories explain the behavior of acids and bases. The most common are:
2.1. Arrhenius Theory
Acid: A substance that increases the concentration of H⁺ ions in aqueous solution.
Base: A substance that increases the concentration of OH⁻ ions in aqueous solution.
Example:
HCl→H++Cl−\text{HCl} \rightarrow \text{H}^+ + \text{Cl}^-HCl→H++Cl− (Acid)
NaOH→Na++OH−\text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^-NaOH→Na++OH− (Base)
2.2. Bronsted-Lowry Theory
Acid: A proton (H⁺) donor.
Base: A proton (H⁺) acceptor.
Example:
In the reaction between HCl and water: HCl+H2O→H3O++Cl−\text{HCl} +
\text{H}_2\text{O} \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^-HCl+H2O→H3O++Cl− Here,
HCl donates a proton (H⁺), acting as an acid, and water acts as a base by accepting the
proton.
2.3. Lewis Theory
Acid: A substance that can accept a pair of electrons.
Base: A substance that can donate a pair of electrons.
Example:
