CSS - PMS - CCE - PCS - General Science
Acid/Base
Phenolphthalein becomes which color in a basic solution?
A. Pink
B. Colorless
C. Orange
D. Green
Correct Answer: A
A: Correct because phenolphthalein becomes pink in a sufficiently basic solution. B: Incorrect because colorless is its acidic or near-neutral appearance. C: Incorrect because orange is associated with some other indicators, not phenolphthalein. D: Incorrect because green is not the characteristic basic color of phenolphthalein.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Phenolphthalein is usually what color in an acidic solution?
A. Pink
B. Red
C. Colorless
D. Blue
Correct Answer: C
A: Incorrect because pink appears in sufficiently basic solution. B: Incorrect because red is not its normal acidic color. C: Correct because phenolphthalein is colorless in acidic and near-neutral solutions. D: Incorrect because blue is not a phenolphthalein color.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What happens to red litmus paper in a basic solution?
A. It turns blue
B. It turns red
C. It becomes colorless
D. It turns yellow
Correct Answer: A
A: Correct because bases turn red litmus paper blue. B: Incorrect because red is the original color and does not show a basic change. C: Incorrect because colorless is not the normal litmus response. D: Incorrect because yellow is not the characteristic basic litmus color.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What happens to blue litmus paper in an acidic solution?
A. It turns red
B. It turns blue
C. It becomes pink
D. It remains green
Correct Answer: A
A: Correct because acids turn blue litmus paper red. B: Incorrect because blue is the original color and indicates no acidic change. C: Incorrect because pink is associated with phenolphthalein in bases, not litmus in acids. D: Incorrect because green is not the characteristic acidic litmus result.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which statement correctly distinguishes acid strength from concentration?
A. Strength is the amount of acid present; concentration is ionization.
B. Strength is degree of ionization; concentration is amount per unit volume.
C. They always mean exactly the same thing.
D. Only weak acids can be concentrated.
Correct Answer: B
A: Incorrect because the two definitions are reversed. B: Correct because strength refers to the extent of ionization, whereas concentration refers to how much solute is present per unit volume. C: Incorrect because strength and concentration are different properties. D: Incorrect because a weak acid solution can be concentrated, and a strong acid solution can be dilute.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is a weak base?
A. KOH
B. NaOH
C. NH₃
D. Ba(OH)₂
Correct Answer: C
A: Incorrect because KOH is a strong base. B: Incorrect because NaOH is a strong base. C: Correct because NH₃ accepts protons from water only partially, so it is a weak base. D: Incorrect because soluble Ba(OH)₂ dissociates strongly.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is a strong base?
A. NH₃
B. NaOH
C. NH₄OH
D. Al(OH)₃
Correct Answer: B
A: Incorrect because NH₃ is a weak base. B: Correct because NaOH dissociates essentially completely in water and is a strong base. C: Incorrect because NH₄OH is a conventional representation of aqueous ammonia and is weak. D: Incorrect because Al(OH)₃ is sparingly soluble and amphoteric.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is a weak acid?
A. HCl
B. HNO₃
C. CH₃COOH
D. HClO₄
Correct Answer: C
A: Incorrect because HCl is a strong acid. B: Incorrect because HNO₃ is a strong acid. C: Correct because acetic acid, CH₃COOH, ionizes only partially in water. D: Incorrect because HClO₄ is a strong acid.
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.