Arrhenius acid is a substance that produces hydrogen ion (H⁺) when dissolved in water while Arrhenius base is a substance that produces hydroxyl/hydroxide ion (OH⁻) when dissolved in water. This Arrhenius definition focuses more on dissolving these substances in water and does not explain what happens when an acid is dissolved in other solvents (like ethanol). However, Bronsted-Lowry's definition of acid and base took care of this "lapse".
Bronsted-lowry acid is a substance that donates a proton or hydrogen ion (H⁺) while a Bronsted-lowry base is a substance that receives a proton or hydrogen ion (H⁺).
