According to Arrhenius, acids such as citric acid and acetic acid are classified as acids because their aqueous solutions contain which species?

According to Arrhenius, acids such as citric acid and acetic acid are classified as acids because their aqueous solutions contain which species?

• A. Hydrogen ions
• B. Hydrogen atoms
• C. Hydroxide ions
• D. Hydroxide atoms

Answer: (A)

The key idea is that acids, by the Arrhenius definition, release hydrogen ions into aqueous solution. Citric acid and acetic acid dissociate to give H+ ions, which in water become hydronium ions (H3O+). It’s this increase in hydrogen ion concentration that makes the solution acidic. The other options don’t fit because acids don’t supply hydroxide ions (those come from bases), and they don’t contain free hydrogen atoms or hydroxide atoms as the species that define acidity in solution.

The key idea is that acids, by the Arrhenius definition, release hydrogen ions into aqueous solution. Citric acid and acetic acid dissociate to give H+ ions, which in water become hydronium ions (H3O+). It’s this increase in hydrogen ion concentration that makes the solution acidic. The other options don’t fit because acids don’t supply hydroxide ions (those come from bases), and they don’t contain free hydrogen atoms or hydroxide atoms as the species that define acidity in solution.