Acid and Base Theories Lecture Notes

A collection of vocabulary flashcards covering the Arrhenius, Brønsted-Lowry, and Lewis theories of acids and bases, including their definitions, examples, and limitations.

Arrhenius Theory

A theory introduced in 1887 by Swedish scientist Svante Arrhenius stating that acids release hydrogen ions ($H^+$) and bases release hydroxide ions ($OH^-$) in aqueous solutions.

Arrhenius Acid

Substances that dissociate in water to release hydrogen ions ($H^+$), such as Hydrochloric acid ($HCl$), Sulfuric acid ($H_2SO_4$), and Carbonic acid ($H_2C_2O_3$).

Arrhenius Base

Substances that release hydroxide ions ($OH^-$) when dissociated in water, such as Sodium hydroxide ($NaOH$), Potassium hydroxide ($KOH$), and Magnesium hydroxide ($MgOH_2$).

Hydronium Ion ($H_3O^+$)

A hydrated hydrogen ion formed when an Arrhenius acid such as $HCl$ dissociates in water.

Hydroxyl Ion

Another name for the hydrated hydroxide ion ($OH^-$) released when an Arrhenius base dissociates in water.

Neutralization Reaction

A reaction where an Arrhenius acid and base react to generate water and salt.

Brønsted-Lowry Theory

A theory developed in 1923 by Johannes Nicolaus Brønsted and Thomas Martin Lowry describing acid-base interactions as the transfer of an $H^+$ ion or proton.

Brønsted-Lowry Acid

Any compound that can transfer a proton ($H^+$) to another compound; it must contain at least one hydrogen atom.

Brønsted-Lowry Base

A compound that accepts a proton ($H^+$) from another compound.

Conjugate Base

The species formed when a Brønsted-Lowry acid loses a proton ($H^+$).

Conjugate Acid

The species formed when a Brønsted-Lowry base gains a proton ($H^+$).

Aprotic Solvents

Solvents like benzene and dioxane where the Brønsted-Lowry theory fails to explain acid-base behavior because no proton transfer occurs.

Lewis Acid

A substance that accepts a pair of electrons to form a covalent bond, according to Gilbert N. Lewis.

Lewis Base

A substance that donates a pair of electrons to form a covalent bond, according to Gilbert N. Lewis.

Ammonia ($NH_3$)

An example of a base that produces hydroxide ions in water ($NH_3 + H_2O \rightarrow NH_4^+ + OH^-$) and is used to demonstrate the limitations of the Arrhenius formula ($BOH$).

Arrhenius Dissociation Equation (Acid)

The general process where an acid splits in water, exemplified by $HCl + H_2O \rightarrow H_3O^+ + Cl^-$.

Arrhenius Dissociation Equation (Base)

The general process where a base separates in water, given as $BOH(aq) \rightarrow OH^-(aq) + B^-(aq)$.