Which substance would be considered an Arrhenius acid?

Which substance would be considered an Arrhenius acid?

• A. HNO3
• B. NaCl
• C. NH3
• D. KOH

Answer: (A)

Arrhenius acids are substances that, when dissolved in water, increase the concentration of hydronium ions (H3O+) by donating a proton (H+). Nitric acid releases H+ in solution to form H3O+ and NO3−, so it makes the solution acidic. Sodium chloride simply dissociates into Na+ and Cl− and doesn’t affect H3O+ levels. Ammonia acts as a base in water, accepting a proton to form NH4+ and OH−, which raises hydroxide instead of hydronium. Potassium hydroxide also provides OH−, not H3O+. Thus, the substance that behaves as an Arrhenius acid is nitric acid.

Arrhenius acids are substances that, when dissolved in water, increase the concentration of hydronium ions (H3O+) by donating a proton (H+). Nitric acid releases H+ in solution to form H3O+ and NO3−, so it makes the solution acidic. Sodium chloride simply dissociates into Na+ and Cl− and doesn’t affect H3O+ levels. Ammonia acts as a base in water, accepting a proton to form NH4+ and OH−, which raises hydroxide instead of hydronium. Potassium hydroxide also provides OH−, not H3O+. Thus, the substance that behaves as an Arrhenius acid is nitric acid.