CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is a basic oxide?
A. SO₂
B. CO₂
C. MgO
D. P₄O₁₀
Correct Answer: C
A: Incorrect because SO₂ is acidic. B: Incorrect because CO₂ is acidic. C: Correct because MgO is a metal oxide that reacts with acids and is classified as basic. D: Incorrect because P₄O₁₀ is an acidic oxide.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which of the following is an acidic oxide?
A. CO₂
B. MgO
C. Na₂O
D. CaO
Correct Answer: A
A: Correct because CO₂ is a nonmetal oxide that forms carbonic acid in water and reacts with bases. B: Incorrect because MgO is a basic metal oxide. C: Incorrect because Na₂O is strongly basic. D: Incorrect because CaO is a basic oxide.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A basic oxide commonly reacts with an acid to form:
A. Salt and water
B. Only hydrogen
C. Only carbon dioxide
D. Another acid only
Correct Answer: A
A: Correct because basic oxides neutralize acids, usually producing salt and water. B: Incorrect because hydrogen is not the sole neutralization product. C: Incorrect because carbon dioxide is not produced from every basic oxide. D: Incorrect because the reaction does not normally produce only another acid.
CSS - PMS - CCE - PCS - General Science
Acid/Base
An acid reacting with a metal oxide generally forms:
A. Salt and water
B. Hydrogen and salt
C. Carbon dioxide only
D. A metal and an acid
Correct Answer: A
A: Correct because many metal oxides are basic and react with acids to form salt and water. B: Incorrect because hydrogen is usually associated with acid–metal reactions. C: Incorrect because carbon dioxide is associated with acid–carbonate reactions. D: Incorrect because metal and acid are not the normal products.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which gas turns limewater milky?
A. Hydrogen
B. Oxygen
C. Carbon dioxide
D. Nitrogen
Correct Answer: C
A: Incorrect because hydrogen does not form calcium carbonate. B: Incorrect because oxygen does not give the limewater test. C: Correct because carbon dioxide reacts with limewater to form insoluble calcium carbonate, causing milkiness. D: Incorrect because nitrogen is generally unreactive in this test.
CSS - PMS - CCE - PCS - General Science
Acid/Base
An acid reacting with a carbonate usually produces:
A. Salt, water, and carbon dioxide
B. Salt and hydrogen only
C. Metal and oxygen
D. Base and chlorine
Correct Answer: A
A: Correct because acid–carbonate reactions produce a salt, water, and carbon dioxide. B: Incorrect because hydrogen is typical of many acid–metal reactions. C: Incorrect because metal and oxygen are not products of acid–carbonate reactions. D: Incorrect because a base and chlorine are not the expected products.
CSS - PMS - CCE - PCS - General Science
Acid/Base
An acid reacting with a suitable active metal usually produces:
A. Salt and hydrogen gas
B. Salt and oxygen gas
C. Base and nitrogen gas
D. Only water
Correct Answer: A
A: Correct because many acids react with active metals to form a salt and hydrogen gas. B: Incorrect because oxygen is not the normal gas in this reaction. C: Incorrect because a base and nitrogen are not typical products. D: Incorrect because water alone is not produced.
CSS - PMS - CCE - PCS - General Science
Acid/Base
What are the products of HCl + NaOH?
A. NaCl and H₂O
B. Na₂SO₄ and H₂
C. Cl₂ and Na
D. HNO₃ and KOH
Correct Answer: A
A: Correct because hydrochloric acid neutralizes sodium hydroxide to form sodium chloride and water. B: Incorrect because sodium sulfate requires sulfuric acid, and hydrogen is not a neutralization product. C: Incorrect because chlorine and sodium metal are not formed in this aqueous neutralization. D: Incorrect because nitric acid and potassium hydroxide are unrelated substances.
CSS - PMS - CCE - PCS - General Science
Acid/Base
A neutralization reaction generally produces:
A. Salt and water
B. Hydrogen and oxygen
C. Only carbon dioxide
D. Metal and acid
Correct Answer: A
A: Correct because an acid reacting with a base generally forms salt and water. B: Incorrect because hydrogen and oxygen are not the usual products of neutralization. C: Incorrect because carbon dioxide forms when acids react with carbonates, not in every neutralization. D: Incorrect because metal and acid are reactants in another reaction type, not products.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Which indicator gives an approximate pH over a wide range?
A. Universal indicator
B. Blue litmus only
C. Phenolphthalein only
D. Methyl orange only
Correct Answer: A
A: Correct because a universal indicator contains a mixture of indicators and shows different colors across a broad pH range. B: Incorrect because blue litmus mainly distinguishes acidic from non-acidic conditions. C: Incorrect because phenolphthalein changes over a limited basic range. D: Incorrect because methyl orange changes over a limited acidic range.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Methyl orange is typically what color in a basic solution?
A. Red
B. Yellow
C. Pink
D. Colorless
Correct Answer: B
A: Incorrect because red is its acidic color. B: Correct because methyl orange is yellow in basic solution. C: Incorrect because pink is associated with phenolphthalein in base. D: Incorrect because methyl orange is not normally colorless in base.
CSS - PMS - CCE - PCS - General Science
Acid/Base
Methyl orange is typically what color in an acidic solution?
A. Yellow
B. Red
C. Blue
D. Purple
Correct Answer: B
A: Incorrect because yellow is its basic color. B: Correct because methyl orange is red in acidic solution. C: Incorrect because blue is not a methyl-orange color. D: Incorrect because purple is not its standard acidic color.
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.