pH scale

What is a Brønsted–Lowry acid

A substance that donates a proton (H⁺) to another species.

What is a Brønsted–Lowry base

A substance that accepts a proton (H⁺) from another species.

How is a proton shown in an acid reaction

The proton appears on the product side of the equation.

How is a proton shown in a base reaction

The proton appears on the reactant side of the equation.

Give an example of a Brønsted–Lowry acid reaction

CH₃COOH ⇌ CH₃COO⁻ + H⁺.

Give an example of a Brønsted–Lowry base reaction

NH₃ + H⁺ ⇌ NH₄⁺.

What is a conjugate acid–base pair

Two species that differ by a single proton (H⁺)

How do you identify the conjugate base of an acid

Subtract one proton (H⁺) from the acid.

How do you identify the conjugate acid of a base

Add one proton (H⁺) to the base.

What does it mean for a substance to be amphiprotic

It can act as both a Brønsted–Lowry acid and a Brønsted–Lowry base.

Give three examples of amphiprotic species

HSO₄⁻

What is a buffer solution

A solution containing a weak acid and its conjugate base

How does a buffer respond when strong acid is added

Added H⁺ is neutralised by the conjugate base

How does a buffer respond when strong base is added

Added OH⁻ neutralises H₃O⁺

Why can buffers resist pH changes

Because Le Châtelier’s principle shifts the equilibrium to counteract added H⁺ or OH⁻