What are Arrhenius bases?

Hint: As we know that the Arrhenius is one of the concepts for acid and bases. Swedish chemist Arrhenius is the world's first chemist to tell about acid and bases. Depending on his concept and limitations later so many concepts are developed. Even Arrhenius is the birthplace of the concept of acids and bases. Followed by Arrhenius chemist the concept of acids and bases discuss Bronsted and Lowry in the world.

Complete step by step answer:
We have to know that according to Arrhenius concept one substance said to acid means, acid is nothing but a substance that dissociates to give hydrogen ion when decompose in the water.
We have to remember that examples of Arrhenius acids are hydrochloric acid (\[{\text{HCl}}\]), sulphuric acid (\[{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}\]), nitric acid (\[{\text{HN}}{{\text{O}}_{\text{3}}}\]) etc,.
According to Arrhenius concept one substance said to base means, bases is nothing but a substance that dissociates to give hydroxyl ion when decompose in water.
Examples of Arrhenius bases are sodium hydroxide (\[{\text{NaOH}}\]), calcium hydroxide (\[{\text{Ca(OH}}{{\text{)}}_{\text{2}}}\]) etc,.
Hence, sodium hydroxide (\[{\text{NaOH}}\]) and calcium hydroxide (\[{\text{Ca(OH}}{{\text{)}}_{\text{2}}}\]) are consider as Arrhenius bases.

Note: We also remember that in generally, pH value of all acids are in between \[{\text{0}}{\text{.9 - 6}}{\text{.9}}\] and all the bases are in between\[7.1 - 14.0\]. But, Arrhenius theory has some limitations. One of the main limitations is not being able to explain the behaviour of acids and bases in non-aqueous solvents such as acetone etc,. It is not possible to explain the acid which doesn't contain hydrogen and bases don’t contain hydroxyl ions in the formula. Ammonia is a well known base and is not accepted as a base in Arrhenius. These limitations are recovered by further coming theories like Bronsted and Lowry concept of acids and bases.