Questions on Arrhenius Acids
20 Multiple-Choice Questions on Arrhenius Acids
1. According to Arrhenius, an acid is a substance that:
A) Accepts a proton
B) Donates OH⁻ ions in water
C) Produces H⁺ ions in water
D) Has a sour taste
E) Neutralizes bases
2. Which of the following is an Arrhenius acid?
A) NaOH
B) NH₃
C) HCl
D) NaCl
E) KOH
3. The Arrhenius definition of acids is limited because:
A) It only applies to strong acids
B) It includes bases as acids
C) It applies only in aqueous solutions
D) It only applies to organic compounds
E) It ignores pH completely
4. Which of the following is not a correct example of an Arrhenius acid?
A) HNO₃ → H⁺ + NO₃⁻
B) HCl → H⁺ + Cl⁻
C) H₂SO₄ → 2H⁺ + SO₄²⁻
D) NaOH → Na⁺ + OH⁻
E) HBr → H⁺ + Br⁻
5. When dissolved in water, HCl acts as an Arrhenius acid because it:
A) Accepts an electron
B) Produces OH⁻ ions
C) Donates a hydrogen atom
D) Produces H⁺ ions
E) Forms a solid
6. Which of these properties is directly related to the Arrhenius acid definition?
A) Forms conjugate base
B) Has a bitter taste
C) Increases [H⁺] in solution
D) Accepts protons
E) Has a low boiling point
7. Which of the following substances can be classified as an Arrhenius acid but not as a Bronsted-Lowry acid?
A) HCl
B) HNO₃
C) H₂SO₄
D) There is no such substance
E) NH₄⁺
8. Which statement best describes how an Arrhenius acid behaves in water?
A) Releases electrons
B) Increases OH⁻ ion concentration
C) Produces H⁺ ions
D) Dissociates into covalent compounds
E) Forms basic solutions
9. Which of the following reactions demonstrates an Arrhenius acid?
A) NH₃ + H₂O → NH₄⁺ + OH⁻
B) HCl + H₂O → H₃O⁺ + Cl⁻
C) NaOH → Na⁺ + OH⁻
D) CH₄ → C⁺ + H⁻
E) CO₂ + H₂O → H₂CO₃
10. Which of the following best fits the Arrhenius acid definition?
A) HCl
B) NaCl
C) CH₃CH₂OH
D) NH₃
E) O₂
11. The acid behavior in the Arrhenius theory is strictly based on:
A) The presence of OH⁻
B) The type of solvent
C) Production of H⁺ in water
D) A low electronegativity
E) Base neutralization only
12. What ion is produced by all Arrhenius acids in water?
A) Cl⁻
B) OH⁻
C) Na⁺
D) H⁺
E) NO₃⁻
13. Which of the following best explains why Arrhenius acids increase conductivity in water?
A) They produce salt
B) They form covalent bonds
C) They produce hydrogen gas
D) They release ions that conduct electricity
E) They are neutral
14. Which is a limitation of the Arrhenius theory?
A) It does not apply to strong acids
B) It excludes non-electrolytes
C) It excludes acid-base reactions not in water
D) It includes ionic compounds
E) It defines acids by pH only
15. Which of these is the best Arrhenius acid for lowering the pH of a solution?
A) NaOH
B) NH₃
C) HCl
D) CH₄
E) NaCl
16. H₂SO₄ is classified as an Arrhenius acid because it:
A) Reacts with bases
B) Accepts electrons
C) Produces OH⁻
D) Produces H⁺ in water
E) Dissolves salts
17. Which compound increases [H⁺] in solution and fits the Arrhenius acid definition?
A) NaOH
B) H₂O
C) HNO₃
D) Ca(OH)₂
E) Na₂CO₃
18. The effect of an Arrhenius acid on litmus paper is to:
A) Turn it blue
B) Turn it red
C) Leave it unchanged
D) Turn it green
E) Bleach it white
19. The role of H₃O⁺ in acid solutions reflects that:
A) All Arrhenius acids are weak
B) H⁺ does not exist freely in water
C) OH⁻ is always present
D) Arrhenius acids cannot form ions
E) Water cannot accept protons
20. Which of these best summarizes the Arrhenius definition of an acid?
A) Accepts H⁺
B) Donates OH⁻
C) Increases H⁺ in aqueous solution
D) Reacts with carbonates
E) Tastes sour
Answer Key with Extended Explanations
1. C – Arrhenius acids produce H⁺ ions when dissolved in water.
2. C – HCl is a classic Arrhenius acid; it dissociates to give H⁺ and Cl⁻.
3. C – The definition only works in aqueous solutions, excluding gaseous or non-aqueous systems.
4. D – NaOH is a base, not an acid.
5. D – HCl releases H⁺ in water, making it an Arrhenius acid.
6. C – Arrhenius acids increase hydrogen ion concentration in solution.
7. D – All Arrhenius acids are also Bronsted-Lowry acids; there is no such example.
8. C – Producing H⁺ ions is the defining feature of Arrhenius acids in water.
9. B – HCl dissociates in water to produce H₃O⁺ and Cl⁻ (H⁺ + H₂O = H₃O⁺).
10. A – HCl clearly fits the Arrhenius acid definition.
11. C – The definition revolves around H⁺ ion production in aqueous solution.
12. D – H⁺ is the common ion produced by all Arrhenius acids.
13. D – Free ions in solution conduct electricity; acids release H⁺.
14. C – Arrhenius theory only applies to aqueous reactions.
15. C – HCl dissociates completely and drastically lowers pH.
16. D – H₂SO₄ releases H⁺ ions in water.
17. C – HNO₃ increases H⁺ in water, making it an Arrhenius acid.
18. B – Acids turn blue litmus paper red.
19. B – Free H⁺ ions immediately associate with water to form H₃O⁺.
20. C – The formal definition is "increases H⁺ in aqueous solution."
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