Arrhenius Acid-Base Concept 🧪 The Arrhenius concept defines acids and bases based on their behavior in water (aqueous solution). An acid is a substance that produces H⁺ ions (or H₃O⁺ ions) in water. 👉 Example: HCl → H⁺ Cl⁻ A base is a substance that produces OH⁻ ions in water. 👉 Example: NaOH → Na⁺ OH⁻ This theory was proposed by Svante Arrhenius (1884) and is one of the earliest definitions of acids and bases. It works best for aqueous solutions but fails to explain acid-base behavior in non