B

Brønsted-Lowry Acid

HA + B → A⁻ + BH⁺
Quick Reference
Formula / NotationHA + B → A⁻ + BH⁺
Also Known AsProton donor, Brønsted acid, protic acid, protonic acid

What is Brønsted-Lowry Acid?

A Brønsted-Lowry acid is any species capable of donating a proton (H⁺) to another species. This definition, proposed independently by Johannes Brønsted and Thomas Lowry in 1923, extends the earlier Arrhenius definition by not requiring the presence of water. Every Brønsted-Lowry acid has a conjugate base formed by the loss of a proton.

Formula & Notation

HA + B → A⁻ + BH⁺

Other Names / Synonyms: Proton donor, Brønsted acid, protic acid, protonic acid

Properties & Characteristics

A Brønsted-Lowry acid is any species that can donate a proton (H⁺) to another species. Defined by Johannes Brønsted and Thomas Lowry (1923), this definition extends beyond Arrhenius acids (which only liberate H⁺ in water) to non-aqueous systems. Every Brønsted acid has a conjugate base (A⁻). Acid strength is measured by Ka (or pKa); strong acids (HCl, H₂SO₄) fully dissociate, while weak acids partially dissociate.

Uses & Applications

Brønsted-Lowry acid-base theory underpins titration chemistry, buffer design, biochemical pH regulation, and industrial acid-catalysed reactions (esterification, cracking). It explains proton transfer in enzymes and in synthesis of pharmaceuticals and fine chemicals.

Safety Information

Strong Brønsted acids (H₂SO₄, HCl, HNO₃) are severely corrosive to skin, eyes, and respiratory tract. Always use acid-resistant PPE (nitrile gloves, safety glasses, lab coat) and work in ventilated areas. Neutralise spills with sodium bicarbonate.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Brønsted-Lowry Acid
Formula HA + B → A⁻ + BH⁺
Synonyms Proton donor, Brønsted acid, protic acid, protonic acid

Frequently Asked Questions

A Brønsted-Lowry acid is any species capable of donating a proton (H⁺) to another species. This definition, proposed independently by Johannes Brønsted and Thomas Lowry in 1923, extends the earlier Arrhenius definition by not requiring the presence of water. Every Brønsted-Lowry acid has a conjugate base formed by the loss of a proton.

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