Question

What is Ionisation theory ?

Answer 1

Ionization theory: The ionization theory was given by Arrhenius which is popularly known as Arrhenius's theory of ionization.

• According to Arrhenius's theory of ionization, the substances which contain hydrogen ion$\left({\mathrm{H}}^{+}\right)$ and that dissociates to form hydrogen ion in aqueous solution are known as acids.
• The substances which contain hydroxyl ions and when dissolved in water give hydroxide ions (${\mathrm{OH}}^{-}$) are called base.
• The extent of ionization depends on the nature of the electrolyte whether it is weak or strong.

Ionization of strong acid: Strong acids like Hydrochloric acid are completely dissociated into the respective ions.

• The dissociation of hydrochloric acid can be represented as:

$\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}\stackrel{}{\to }\underset{\mathrm{Hydrogen}\mathrm{ion}}{{\mathrm{H}}^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Chloride}\mathrm{ion}}{{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)}$

Ionization of strong base: Strong bases like Sodium hydroxide are completely dissociated into the respective ions.

• The dissociation of Sodium hydroxide can be represented as:

$\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}\stackrel{}{\to }\underset{\mathrm{Sodium}\mathrm{ion}}{{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydroxide}\mathrm{ion}}{{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$