Question

The theory of ionisation was presented by
A. Faraday
B. Arrhenius
C. Ostwald
D. Rutherford

Answer 1

When a neutral molecule is introduced to a solution, it undergoes ionisation, which is defined as the process by which it breaks into charged ions. Arrhenius theory was introduced in $1887$ by the Swedish scientist Svante Arrhenius.

Complete answer:
Because most ionisation occurs in an aqueous medium, the Arrhenius theory is important in explaining acid and basic ionisation. The strength of acids and bases can be determined by the degree of ionisation of both acids and bases. In addition, the degree of ionisation varies between acidic and basic substances. Acids such as perchloric acid ($HCl{O_4}$), hydrochloric acid ($HCl$) dissociate into their constituent ions in an aqueous medium.
These acids are all classified as strong acids. Acids produce hydrogen ions when they are ionised, and as a result, these substances operate as proton donors. In an aqueous solution or media, a few bases, such as sodium hydroxide ($NaOH$) and lithium hydroxide ($LiOH$), dissociate entirely into their ions. Strong bases are the name given to these types of foundations. Hydroxyl ions are formed when these bases are ionised.
As a result, the degree of ionisation of acids and bases is determined by the degree of dissociation of compounds into constituent ions. When compared to the ionisation of weak acids and bases, strong acids and bases have a higher degree of ionisation. A strong acid is also an excellent proton donor, whereas a strong base is a good proton acceptor, as demonstrated by the dissociation of the weak acid $HA$.
$HA\left( {aq} \right){\text{ }} + {\text{ }}{H_2}O\left( l \right){\text{ }} \rightleftharpoons {\text{ }}{H_3}{O^ + }{\text{ }}\left( {aq} \right){\text{ }} + {\text{ }}{A^ - }\left( {aq} \right)$

Hence, the correct option is B. Arrhenius.

Note:
Strong acids tend to have weaker conjugate bases, while strong bases tend to have weaker conjugate acids. Strong acids and bases have a high degree of ionisation, which causes this.