Basic chemistry

What is Bronsted Lowry concept of acid and base?

Bronsted Lowry concept?

Bronsted Lowry concept:

Bronsted Lowry concept,A  more general acid-base theory, the Brønsted-Lowry theory.

It is named after the Danish chemist Johannes Nicolaus Brønsted and the English chemist Thomas Martin Lowry, defines an acid as a proton donor and a base as a proton acceptor.

In the theory, the reaction of an acid and base is represented as an equilibrium reaction.

acid (1) + base (2) ⇌ base (1) + acid (2)(The double arrows, ⇌, indicate that the products can re-form the reactants in a dynamic process.)

HCl + NaOH → NaCl + H2O


Acid (1) and base (1) are called a conjugate acid-base pair, as are acid (2) and base (2).

The advantage of this theory is its predictive capacity. Whether the equilibrium lies toward the reactants (reactant-favoured) or the products (product-favoured) is determined by the relative strengths of the acids and bases.

This theory is often closely associated with the solvent water. Dissolving an acid in water to form the hydronium ion and the anion of the acid is an acid-base reaction.

Acids are classified as strong or weak, depending on whether the equilibrium favours the reactants or products.

Hydrochloric acid, a strong acid, ionizes completely in water to form the hydronium and chlorine (Cl) ions in a product-favoured reaction.

HCl(aq) + H2O (l) → H3O+(aq) +Cl

Using the Brønsted-Lowry theory, the reaction of ammonia and hydrochloric acid in water is represented by the following equation:

NH3(aq) + HCl(aq) → NH4+(aq) + Cl

Hydrochloric acid and the chlorine ion are one conjugate acid-base pair, and the ammonium ion and ammonia are the other.

Acid-base reaction is the transfer of the hydrogen ion from the acid (HCl) to the base (NH3).

The equilibrium favours the weaker acid and base, in this case the products.

It is Noted that the hydroxide ion does not appear in this equation, and a point differentiating the Arrhenius and Brønsted-Lowry theories…

you may also look on this theory of acids and bases

Lewis theory of acid and bases?

Read also:

Definition of bronsted Lowry acid?

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