What distinguishes a weak acid from a strong acid in terms of its behaviour in aqueous solution?

A weak acid is only partially dissociated in aqueous solution, whereas a strong acid is completely dissociated

How does the degree of dissociation distinguish strong acids from weak acids?

Strong acids have a degree of dissociation of essentially 1 (complete dissociation), whereas weak acids have a degree of dissociation much less than 1 (partial dissociation).

What assumption is made about the equilibrium concentration of a weak acid HA when the degree of dissociation is small?

The equilibrium concentration of HA approximately equals the initial concentration of the acid.

Edexcel A-Level Chemistry 9CH0

Atomic Structure and the Periodic Table

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Acid-Base Equilibria

Strong and weak acids, Ka and Kw

3 things to know
Papers 1 and 3

Overview

Recall questions on full and partial dissociation, on writing Ka and pKa, and on the ionic product of water and its role in alkali calculations.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What separates a strong acid from a weak one?

Key term

For a strong monoprotic acid, what is the relationship between hydrogen ion concentration and acid concentration?

Key term

What does it mean for an acid to be described as strong?

Questions from this subtopic

Each one with the model answer underneath.

1
What does it mean for an acid to be described as strong?
Model answer
A strong acid is completely dissociated in aqueous solution.
2
What distinguishes a weak acid from a strong acid in terms of its behaviour in aqueous solution?
Model answer
A weak acid is only partially dissociated in aqueous solution, whereas a strong acid is completely dissociated
3
How does the degree of dissociation distinguish strong acids from weak acids?
Model answer
Strong acids have a degree of dissociation of essentially 1 (complete dissociation), whereas weak acids have a degree of dissociation much less than 1 (partial dissociation).
4
For a strong monoprotic acid, what is the relationship between hydrogen ion concentration and acid concentration?
Model answer
The hydrogen ion concentration equals the acid concentration because the acid is fully dissociated.
5
Write Kₐ for the weak acid HA.
Model answer
Kₐ = [H⁺][A⁻] / [HA]
6
What assumption is made about the equilibrium concentration of a weak acid HA when the degree of dissociation is small?
Model answer
The equilibrium concentration of HA approximately equals the initial concentration of the acid.

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Strong and weak acids, Ka and Kw

Overview

What you need to know

What separates a strong acid from a weak one?

For a strong monoprotic acid, what is the relationship between hydrogen ion concentration and acid concentration?

What does it mean for an acid to be described as strong?

Questions from this subtopic

What does it mean for an acid to be described as strong?

What distinguishes a weak acid from a strong acid in terms of its behaviour in aqueous solution?

How does the degree of dissociation distinguish strong acids from weak acids?

For a strong monoprotic acid, what is the relationship between hydrogen ion concentration and acid concentration?

Write Kₐ for the weak acid HA.

What assumption is made about the equilibrium concentration of a weak acid HA when the degree of dissociation is small?

Other ways to work this

What is inside Levo

The 3-step method, run for you

Cram a whole paper in one sitting

Blank Blitz makes facts automatic

Build It gets the exam shape right

Test It catches misconceptions

Brain Breaks between sessions

Every question in Acid-Base Equilibria, on a schedule.