CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is a strong acid in water?
A. CH₃COOH
B. HCl
C. H₂CO₃
D. Citric acid
Correct Answer: B
A: Incorrect because acetic acid is weak. B: Correct because HCl ionizes essentially completely in water and is classified as a strong acid. C: Incorrect because carbonic acid is weak. D: Incorrect because citric acid is weak.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Ammonia, NH₃, is classified in water as a:
A. Strong acid
B. Weak acid
C. Strong base
D. Weak base
Correct Answer: D
A: Incorrect because ammonia is not an acid. B: Incorrect because ammonia is not an acid. C: Incorrect because it ionizes only partially, so it is not a strong base. D: Correct because ammonia partially reacts with water to form NH₄⁺ and OH⁻, so it is a weak base.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Milk of magnesia mainly contains:
A. Mg(OH)₂
B. MgCl₂
C. NaOH
D. CaCO₃
Correct Answer: A
A: Correct because milk of magnesia is a suspension of magnesium hydroxide, Mg(OH)₂. B: Incorrect because MgCl₂ is magnesium chloride. C: Incorrect because NaOH is sodium hydroxide and is too caustic for this use. D: Incorrect because CaCO₃ is calcium carbonate.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Slaked lime has the formula:
A. CaO
B. Ca(OH)₂
C. CaCO₃
D. CaCl₂
Correct Answer: B
A: Incorrect because CaO is quicklime. B: Correct because slaked lime is calcium hydroxide, Ca(OH)₂. C: Incorrect because CaCO₃ is calcium carbonate. D: Incorrect because CaCl₂ is calcium chloride.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Potassium hydroxide is commonly called:
A. Caustic soda
B. Caustic potash
C. Quicklime
D. Washing soda
Correct Answer: B
A: Incorrect because caustic soda is NaOH. B: Correct because potassium hydroxide, KOH, is commonly known as caustic potash. C: Incorrect because quicklime is CaO. D: Incorrect because washing soda is Na₂CO₃·10H₂O.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Sodium hydroxide is commonly called:
A. Caustic soda
B. Caustic potash
C. Slaked lime
D. Baking soda
Correct Answer: A
A: Correct because sodium hydroxide, NaOH, is commonly known as caustic soda. B: Incorrect because caustic potash is KOH. C: Incorrect because slaked lime is Ca(OH)₂. D: Incorrect because baking soda is NaHCO₃.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Carbonic acid is represented by:
A. H₂CO₃
B. H₂SO₃
C. HClO
D. H₃BO₃
Correct Answer: A
A: Correct because carbonic acid has the formula H₂CO₃. B: Incorrect because H₂SO₃ is sulfurous acid. C: Incorrect because HClO is hypochlorous acid. D: Incorrect because H₃BO₃ is boric acid.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Acetic acid has the formula:
A. HCOOH
B. CH₃COOH
C. H₂SO₄
D. NaHCO₃
Correct Answer: B
A: Incorrect because HCOOH is formic acid. B: Correct because acetic or ethanoic acid is CH₃COOH. C: Incorrect because H₂SO₄ is sulfuric acid. D: Incorrect because NaHCO₃ is sodium hydrogen carbonate.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What is the chemical formula of nitric acid?
A. HNO₃
B. H₂SO₄
C. H₃PO₄
D. H₂CO₃
Correct Answer: A
A: Correct because nitric acid has the formula HNO₃. B: Incorrect because H₂SO₄ is sulfuric acid. C: Incorrect because H₃PO₄ is phosphoric acid. D: Incorrect because H₂CO₃ is carbonic acid.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What is the chemical formula of sulfuric acid?
A. HCl
B. H₂SO₄
C. HNO₃
D. CH₃COOH
Correct Answer: B
A: Incorrect because HCl is hydrochloric acid. B: Correct because sulfuric acid has the formula H₂SO₄. C: Incorrect because HNO₃ is nitric acid. D: Incorrect because CH₃COOH is acetic acid.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What is the chemical name of HCl?
A. Hydrochloric acid
B. Sulfuric acid
C. Nitric acid
D. Carbonic acid
Correct Answer: A
A: Correct because HCl in aqueous solution is hydrochloric acid. B: Incorrect because sulfuric acid is H₂SO₄. C: Incorrect because nitric acid is HNO₃. D: Incorrect because carbonic acid is H₂CO₃.
CSS - PMS - CCE - PCS - General Science
Acid/Base
The commonly used pH scale for dilute aqueous solutions usually ranges from:
A. 0 to 7
B. 1 to 10
C. 0 to 14
D. 7 to 21
Correct Answer: C
A: Incorrect because 0 to 7 covers only acidic to neutral values. B: Incorrect because 1 to 10 omits many common acidic and basic values. C: Correct because the conventional school-level pH scale for dilute aqueous solutions is 0 to 14, although extreme solutions can fall outside it. D: Incorrect because 7 to 21 is not the standard classroom pH range.
CSS - PMS - CCE - PCS - General Science
Acid/Base
The pH of pure water at 25°C is approximately:
A. 0
B. 5
C. 7
D. 14
Correct Answer: C
A: Incorrect because pH 0 is strongly acidic. B: Incorrect because pH 5 is acidic. C: Correct because pure water has equal H⁺ and OH⁻ concentrations of about 1 × 10⁻⁷ M, giving pH 7. D: Incorrect because pH 14 is strongly basic on the common aqueous scale.
CSS - PMS - CCE - PCS - General Science
Acid/Base
At 25°C, a solution with pH greater than 7 is generally:
A. Acidic
B. Basic
C. Neutral
D. Pure water
Correct Answer: B
A: Incorrect because acidic solutions generally have pH below 7. B: Correct because at 25°C, pH values above 7 indicate a basic or alkaline solution. C: Incorrect because neutral water has pH 7 at 25°C. D: Incorrect because pure water is neutral at 25°C.
CSS - PMS - CCE - PCS - General Science
Acid/Base
At 25°C, a solution with pH less than 7 is generally:
A. Acidic
B. Basic
C. Neutral
D. Always a buffer
Correct Answer: A
A: Correct because at 25°C, pH values below 7 indicate an acidic aqueous solution. B: Incorrect because basic solutions generally have pH above 7. C: Incorrect because neutral water has pH 7 at 25°C. D: Incorrect because a buffer may be acidic or basic; pH below 7 does not always mean it is a buffer.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A Lewis base is best described as:
A. Electron-pair donor
B. Electron-pair acceptor
C. Proton donor
D. Salt producer only
Correct Answer: A
A: Correct because a Lewis base donates an electron pair. B: Incorrect because electron-pair acceptance defines a Lewis acid. C: Incorrect because proton donation defines a Brønsted acid. D: Incorrect because many reactions form salts, but this is not the defining feature of a Lewis base.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A Lewis acid is best described as:
A. Electron-pair donor
B. Electron-pair acceptor
C. Proton donor only
D. Hydroxide-ion donor
Correct Answer: B
A: Incorrect because electron-pair donation defines a Lewis base. B: Correct because a Lewis acid accepts an electron pair to form a coordinate bond. C: Incorrect because Lewis acids are broader than proton donors only. D: Incorrect because hydroxide donation is not the Lewis-acid definition.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A Brønsted–Lowry base is a substance that:
A. Donates a proton
B. Accepts a proton
C. Produces H⁺ only
D. Accepts neutrons
Correct Answer: B
A: Incorrect because proton donation defines a Brønsted–Lowry acid. B: Correct because a Brønsted–Lowry base accepts a proton. C: Incorrect because producing H⁺ is not the definition of a Brønsted base. D: Incorrect because neutron acceptance is unrelated to acid–base chemistry.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A Brønsted–Lowry acid is a substance that:
A. Accepts a proton
B. Donates a proton
C. Accepts an electron pair
D. Produces only OH⁻
Correct Answer: B
A: Incorrect because proton acceptance defines a Brønsted–Lowry base. B: Correct because a Brønsted–Lowry acid donates a proton, H⁺, to another species. C: Incorrect because electron-pair acceptance defines a Lewis acid. D: Incorrect because production of OH⁻ is associated with Arrhenius bases.
CSS - PMS - CCE - PCS - General Science
Acid/Base
According to Arrhenius, a base produces which ion in aqueous solution?
A. H⁺
B. OH⁻
C. Cl⁻
D. HCO₃⁻
Correct Answer: B
A: Incorrect because H⁺ characterizes an Arrhenius acid. B: Correct because an Arrhenius base increases the concentration of hydroxide ions in water. C: Incorrect because Cl⁻ is a spectator ion in many reactions. D: Incorrect because HCO₃⁻ can act as a base but is not the defining Arrhenius ion.