CS: 6.3 Strength of acids and alkalis
LS: 6.3.1 Define strong acid, weak acid, strong alkali and weak alkali.
6.3.2 Explain the strength of acid and alkali based on its degree of dissociation in water.
LO: At the end of this lesson, pupils will be able to:
Differentiate strong acid, weak acid, strong alkali and weak alkali by answering the questions correctly.
Explain the strength of acid and alkali based on its degree of association in water.
You already know from the previous lesson that we can determine whether a solution is an acid or base and we can also determine the strength of an acid and base is strong or weak based on their pH value. Now the question is...What makes an acid and alkali strong or weak?
Acid is any substance which when dissolved in water gives hydrogen ions, according to Arrhenius theory.
Depending on the extent of ionization, acids are further classified as weak acid and strong acid.
Any substance which give less number of H+ ions ,when dissolved in water, is known as weak acid. e.g. CH₃-COOH
Any substance which give large number of H+ ions ,when dissolved in water, is known as strong acid. For instance, HCl, Hâ‚‚SOâ‚„ etc.
The similar concept applied to the base.
To find out more about what makes an acid and alkali strong or weak, watch the video attached below:
Now that you know what makes the acid and alkali strength or weak, you can answer a few questions related to the topic to test your understanding. The link of the questions is attached below: