Question

Explain the term acidity of a base?

Answer 1

Definition for Acidity of a base:

• The number of replaceable hydroxyl groups per molecule of the base is called acidity of a base.

Determination whether a substance is an acid or base

• It can be determined by counting the hydrogens on each substance before and after the reaction.
• If the number of hydrogens has decreased then that substance is the acid , if it has increased then that is the base.

Types of bases:

Monoacidic base:

• It contains one replaceable hydroxyl ion (OH^-) per molecule of the water soluble base.

Example: $NaOH\left(s\right)\to N{a}^{+}\left(aq\right)+O{H}^{-}\left(aq\right)$

Diacidic base:

• It contains two replaceable hydroxyl (OH^-) ions per molecule of the water soluble base.

Example: $Mg{\left(OH\right)}_2\left(s\right)\to M{g}^{2+}\left(aq\right)+2O{H}^{-}\left(aq\right)$

Triacidic base:

• It contains three replaceable hydroxyl ions (OH^-) per molecule of the water soluble base.

Example: $Al{\left(OH\right)}_3\left(s\right)\to A{l}^{3+}\left(aq\right)+3O{H}^{-}\left(aq\right)$