Questions on Arrhenius Bases
20 Multiple-Choice Questions on Arrhenius Bases
1. According to the Arrhenius definition, a base is a substance that:
A) Donates a proton in water
B) Produces H⁺ ions in water
C) Accepts protons from acids
D) Produces OH⁻ ions in water
E) Has a sour taste
2. Which of the following is an Arrhenius base?
A) HCl
B) NH₃
C) NaOH
D) H₂SO₄
E) CO₂
3. What ion is common to all Arrhenius bases in aqueous solution?
A) H⁺
B) Cl⁻
C) OH⁻
D) Na⁺
E) NH₄⁺
4. When NaOH dissolves in water, it acts as an Arrhenius base because it:
A) Accepts electrons
B) Produces H⁺ ions
C) Produces OH⁻ ions
D) Neutralizes acids
E) Tastes salty
5. Which of the following is not an Arrhenius base?
A) KOH
B) NH₃
C) LiOH
D) Ba(OH)₂
E) NaOH
6. Which of the following substances increases the concentration of hydroxide ions in aqueous solution?
A) HNO₃
B) H₂O
C) NaOH
D) CO₂
E) CH₃OH
7. An Arrhenius base in water will always:
A) React with a salt
B) Decrease [H⁺]
C) Increase [OH⁻]
D) Turn red litmus paper red
E) Release hydrogen gas
8. Which of the following is a strong Arrhenius base?
A) NH₃
B) NaOH
C) CH₃NH₂
D) H₂O
E) HCl
9. Aqueous NaOH is considered an Arrhenius base because:
A) It donates hydrogen ions
B) It accepts electrons
C) It forms H₃O⁺
D) It dissociates to give OH⁻ ions
E) It produces salt
10. Which of the following compounds dissociates completely in water to form two OH⁻ ions per formula unit?
A) NaOH
B) NH₄OH
C) Ca(OH)₂
D) KOH
E) LiOH
11. Which of the following is a limitation of the Arrhenius definition of bases?
A) It excludes polyprotic acids
B) It does not account for nonaqueous systems
C) It includes organic acids
D) It includes hydronium ions
E) It defines acids incorrectly
12. Which of these would increase the pH of an aqueous solution?
A) HCl
B) NaOH
C) H₂SO₄
D) CO₂
E) HNO₃
13. Arrhenius bases are typically:
A) Non-electrolytes
B) Metal oxides
C) Ionic compounds containing OH⁻
D) Weak electrolytes
E) Acids that accept protons
14. Which of the following bases would produce the most OH⁻ ions per mole when fully dissociated?
A) NaOH
B) KOH
C) Ca(OH)₂
D) LiOH
E) Ba(OH)₂
15. What happens when an Arrhenius base is added to an Arrhenius acid?
A) A precipitate forms
B) The pH decreases
C) A neutralization reaction occurs
D) The solution becomes more acidic
E) Oxygen is released
16. Which compound is both a strong electrolyte and a strong Arrhenius base?
A) NH₃
B) NaOH
C) CH₃NH₂
D) H₂O
E) HCO₃⁻
17. Which of the following best describes the effect of an Arrhenius base on red litmus paper?
A) No change
B) Turns it blue
C) Turns it red
D) Dissolves it
E) Bleaches it
18. Which of the following equations demonstrates the behavior of an Arrhenius base?
A) HCl → H⁺ + Cl⁻
B) H₂SO₄ → 2H⁺ + SO₄²⁻
C) NaOH → Na⁺ + OH⁻
D) CO₂ + H₂O → H₂CO₃
E) NH₃ + H₂O → NH₄⁺ + OH⁻
19. Which of the following best represents an Arrhenius base that releases two moles of OH⁻ per mole of substance?
A) NaOH
B) Ba(OH)₂
C) KOH
D) NH₃
E) MgO
20. Why is NH₃ not considered an Arrhenius base?
A) It produces H⁺ ions
B) It has no hydroxide ion
C) It is a gas
D) It accepts protons but doesn’t release OH⁻ directly
E) It reacts only with salts
Answer Key with Extended Explanations
1. D – Arrhenius bases produce hydroxide (OH⁻) ions in aqueous solution.
2. C – NaOH is a classic Arrhenius base.
3. C – All Arrhenius bases release OH⁻ ions.
4. C – NaOH dissociates in water to produce OH⁻ ions.
5. B – NH₃ is a Bronsted-Lowry base, not an Arrhenius base (does not directly produce OH⁻).
6. C – NaOH increases OH⁻ concentration when dissolved.
7. C – By definition, Arrhenius bases increase [OH⁻].
8. B – NaOH is a strong base and dissociates completely in water.
9. D – NaOH dissociates into Na⁺ and OH⁻ ions.
10. C – Ca(OH)₂ gives 2 OH⁻ ions per unit in solution.
11. B – Arrhenius theory applies only in water, excluding other solvents.
12. B – NaOH increases pH by adding OH⁻ to solution.
13. C – Most Arrhenius bases are ionic compounds that contain OH⁻.
14. E – Ba(OH)₂ releases 2 OH⁻ per mole and is highly soluble.
15. C – Bases and acids react to form salt and water (neutralization).
16. B – NaOH is both a strong base and strong electrolyte.
17. B – Bases turn red litmus paper blue.
18. C – This shows NaOH dissociating to form OH⁻ in water.
19. B – Barium hydroxide dissociates to give two OH⁻ per formula unit.
20. D – NH₃ doesn’t release OH⁻ directly; it forms OH⁻ by reacting with water (fits Bronsted-Lowry, not Arrhenius).
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