General Chemistry Competency 3: Differentiating Acid-Base Theories

Vocabulary flashcards covering Arrhenius, Brønsted-Lowry, and Lewis conceptual frameworks in chemical reactions, key terminology, and theoretical relationships.

Arrhenius Acid

A substance that produces $H^+$ ions in aqueous solution.

Arrhenius Base

A substance that produces $OH^-$ ions in aqueous solution.

Brønsted-Lowry Acid

A proton ($H^+$) donor.

Brønsted-Lowry Base

A proton ($H^+$) acceptor.

Lewis Acid

An electron pair acceptor, often an electrophile with an open orbital such as $BF_3$, $AlCl_3$, or $H^+$.

Lewis Base

An electron pair donor, often a nucleophile with a lone pair such as $NH_3$ or $H_2O$.

Arrhenius Theory (1884)

An acid-base theory limited strictly to water ($H_2O$), focusing on aqueous ions ($H^+$ and $OH^-$) where neutralization produces liquid water.

Brønsted-Lowry Theory (1923)

An acid-base theory centered on proton ($H^+$) transfer that applies in any solvent or gas phase.

Lewis Theory (1923)

The broadest and most comprehensive acid-base theory, centered on lone pair electrons without solvent or hydrogen restrictions.

Conjugate Base

The species remaining after a Brønsted-Lowry acid donates a proton, such as $Cl^-$ formed from $HCl$.

Conjugate Acid

The species formed when a Brønsted-Lowry base accepts a proton, such as $NH_4^+$ formed from $NH_3$.

Amphoteric Behavior

The ability of a substance, such as water ($H_2O$), to act as either an acid or a base depending on the reacting partner.

Svante Arrhenius

The scientist who proposed the Arrhenius Theory in 1884, defining acid-base behavior based on ion dissociation in aqueous solution.

Gilbert N. Lewis

The chemist who introduced the Lewis acid-base framework in 1923 based on lone pair electron donation and acceptance.

Theoretical Inclusivity Hierarchy

The nested relationship of acid-base theories where all Arrhenius acids/bases are Brønsted-Lowry acids/bases, and all Brønsted-Lowry acids/bases are Lewis acids/bases.

Coordinate Covalent Bond

A chemical bond formed during Lewis acid-base adduct formation when a Lewis base donates a lone pair of electrons to a Lewis acid.

Proton Transfer Reaction Step

A reaction step in a mechanism, such as Fischer esterification, where a proton ($H^+$) moves from one atom to another.