Question

Which of these definitions could be used to define KOH as a base? Check all that apply.

Arrhenius concept

Bronsted-Lowry concept

Lewis concept

Answer 1

All three.

- Arrhenius: yes — KOH dissociates in water to give OH−, increasing the [OH−].
- Brønsted–Lowry: yes — the OH− ion accepts a proton (H+) to form H2O.
- Lewis: yes — the hydroxide ion has lone pairs and can donate an electron pair (e.g., to H+), so it is a Lewis base.