Question

How can I identify an Arrhenius acid?

Answer 1

Hint: We know that acid is a substance of sour taste which turns blue litmus red and also liberates hydrogen with active metals like sodium, calcium, potassium etc. and a base is a substance of bitter taste which turns red litmus blue.

Complete step by step answer:
The above definitions of acids acids and bases were rather vague and there were many exceptions. The modern theories of acids and bases are based upon their structures and composition. There are three theories that define acids and bases namely, Arrhenius concept, Bronsted Lowry concept and Lewis concept.
Let’s discuss the Arrhenius concept of acids and bases in detail. Arrhenius concept explains the ionization of the strong and weak electrolytes in water. Since both the acids and bases are also electrolytes, therefore these are also covered by the concept.
According to Arrhenius concept, an acid is a hydrogen containing compound which gives free hydrogen ions when dissolved in water. For example, when hydrochloric acid is added to the water, it releases hydrogen and chloride ions. So, HCl is an Arrhenius acid.
${\text{HCl}}\xrightarrow{{{\text{Water}}}}{{\text{H}}^ + } + {\text{C}}{{\text{l}}^ - }$
So, an Arrhenius acid releases hydrogen ions on dissolving it in water.

Note: An Arrhenius base is the hydroxyl group containing compounds which give free hydroxyl ions when dissolved in water. For example, sodium hydroxide when added to the water gives sodium ions and hydroxide ions.
${\text{NaOH}}\xrightarrow{{{\text{Water}}}}{\text{N}}{{\text{a}}^{\text{ + }}} + {\text{O}}{{\text{H}}^ - }$
According to the Bronsted Lowry concept, an acid is a substance which has a tendency to donate protons and a base is a substance which has a tendency to accept protons. So, acid is a proton donor and a base is a proton acceptor.