Question

Arrhenius concept is applicable to the acid-base behavior only in the: -
A. Acidic medium
B. Aqueous medium
C. Absence of water
D. None of the above

Answer 1

Arrhenius concept of acids and bases topic knowledge is enough to answer this question. Also, it is a limitation of Arrhenius concept and form dissociation equation of any acid or base could easily predict the answer.

Step by step explanation:
Before proceeding directly to the answer, let us know about the concept behind the question which has asked about Arrhenius concept and its applicability.
A concept was given by a scientist named Arrhenius which explained about the definition of acids and bases. According to Arrhenius, the substance which give out ${H^ + }$ions when dissolved in aqueous solution are termed as acids and those which give out$\;O{H^ - }$ ions when dissolved in aqueous solution are termed as bases.
This could be easily understood by taking some examples of reactions which explains about the substance either as acid or as base.
Example: - $HCl\left( {aq.} \right) \to {\text{ }}{H^ + }\left( {aq.} \right){\text{ }} + {\text{ }}C{l^ - }\left( {aq.} \right)$
In this reaction $HCl$when dissolved in aqueous solution, gives out ${H^ + }$ ions and therefore, $HCl$is acid.
$NaOH\left( {aq.} \right) \to {\text{ }}N{a^ + }\left( {aq.} \right){\text{ }} + {\text{ }}O{H^ - }\left( {aq.} \right)$
In this reaction it gives $\;O{H^ - }$ ion when dissolved in aqueous solution, so it is termed as base.
This concept is only limited to aqueous medium only and definition of acids and bases are applicable when there is aqueous medium. For example: - when $HCl$is dissolved in water (aqueous medium) it acts as acid but when it is dissolved in benzene it will not act as acid.
We see in all of the examples as well as the definition of Arrhenius concept, it is applicable only when substance is dissolved in aqueous solution (mainly water).

Therefore, the correct answer is option B i.e. aqueous medium.

Note: Arrhenius concept of acids and bases and Bronsted-Lowry acid base theory are some topics from which questions can be asked directly and their basic knowledge is sufficient enough to answer such type of questions. There may be questions in which compounds are given and we have to choose which among them is/are acids and bases.