Question 1

What is the Brønsted–Lowry theory of acids and bases?

Accepted Answer

The Brønsted–Lowry theory defines acids as substances that donate protons (H⁺ ions) and bases as substances that accept protons. This theory is fundamental in understanding acid-base equilibria in AS-Level Physical Chemistry, particularly within the Cambridge International A Levels curriculum.

Question 2

How does the Brønsted–Lowry theory differ from the Arrhenius theory?

Accepted Answer

While the Arrhenius theory defines acids and bases in terms of their ability to produce H⁺ and OH⁻ ions in water, the Brønsted–Lowry theory broadens this definition by focusing on proton transfer, making it applicable to a wider range of chemical reactions, including those not occurring in aqueous solutions.

Question 3

Can you give an example of a Brønsted–Lowry acid-base reaction?

Accepted Answer

A classic example is the reaction between ammonia (NH₃) and water (H₂O). In this reaction, NH₃ acts as a Brønsted–Lowry base by accepting a proton from H₂O, which acts as a Brønsted–Lowry acid. This results in the formation of NH₄⁺ and OH⁻ ions.

Question 4

What is a conjugate acid-base pair in the Brønsted–Lowry theory?

Accepted Answer

In the Brønsted–Lowry theory, a conjugate acid-base pair consists of two species that transform into each other by the gain or loss of a proton. For example, in the reaction of acetic acid (CH₃COOH) with water, CH₃COOH and CH₃COO⁻ form a conjugate acid-base pair.

Question 5

Why is the Brønsted–Lowry theory important for understanding equilibria in chemistry?

Accepted Answer

The Brønsted–Lowry theory is crucial for understanding chemical equilibria because it explains how acids and bases interact in reversible reactions. This understanding helps predict the direction of equilibrium shifts and the relative strengths of acids and bases, which are key concepts in AS-Level Physical Chemistry under the Cambridge International A Levels curriculum.

Brønsted–Lowry theory of acids and bases

Learn this Topic

Short Study Notes in the form of Slides

Study Notes & Exam Tips

Practice questions

Past paper style quiz

Assess your understanding

Video lesson

Brønsted–Lowry theory of acids and bases — frequently asked questions