Sarkari Jobs Pakistan
Download App

Acids, Bases and Salts MCQs 2026

52 questions with detailed answers · 20 from past papers · 6 quiz batches available

📚 Chemistry 📄 20 Past-Paper Qs ✓ Free · No Login Needed
🎯 Mock Test

Read each question, think about the answer, then click Show Answer to reveal the correct option and explanation. Load 10 at a time so it stays manageable — perfect for one-topic study sessions on the bus or during a break.

Page 1 of 1 Questions 1–10 of 52
  1. Q1 medium

    Litmus paper turns ___ in basic solutions

    1. A Red
    2. B Colorless
    3. C Yellow
    4. D Blue
    💡 Explanation:

    Bases turn red litmus paper blue, a classic acid-base indicator test.

  2. Q2 medium

    Litmus paper turns ___ in acidic solutions

    1. A Blue
    2. B Green
    3. C Colorless
    4. D Red
    💡 Explanation:

    Acids turn blue litmus paper red, a classic acid-base indicator test.

  3. Q3 medium

    The conjugate base of an acid is formed when the acid

    1. A Gains a proton
    2. B Loses a proton
    3. C Gains an electron pair
    4. D Loses an electron pair
    💡 Explanation:

    After donating a proton, the remaining species is the conjugate base of the acid.

  4. Q4 Past Paper · PPSC/FPSC/NTS medium

    The conjugate acid of a base is formed when the base

    1. A Loses a proton
    2. B Loses an electron pair
    3. C Gains a proton
    4. D Gains hydroxide ions
    💡 Explanation:

    After accepting a proton, the base becomes its conjugate acid.

  5. Q5 Past Paper · PPSC/FPSC/NTS medium

    An acidic buffer is typically prepared from

    1. A A strong acid and its salt
    2. B A strong base and its salt
    3. C Two strong acids
    4. D A weak acid and its conjugate base (salt)
    💡 Explanation:

    Acidic buffers combine a weak acid with a salt of its conjugate base to resist pH changes.

  6. Q6 Past Paper · PPSC/FPSC/NTS medium

    The conjugate acid of a base is formed when the base

    1. A Loses a proton
    2. B Loses an electron pair
    3. C Gains a proton
    4. D Gains hydroxide ions
    💡 Explanation:

    After accepting a proton, the base becomes its conjugate acid.

  7. Q7 easy

    According to the Arrhenius theory, an acid is a substance that

    1. A Accepts protons in solution
    2. B Produces H+ ions in aqueous solution
    3. C Produces OH- ions in aqueous solution
    4. D Accepts electron pairs
    💡 Explanation:

    Arrhenius defined acids as substances that release H+ ions when dissolved in water.

  8. Q8 Past Paper · PPSC/FPSC/NTS easy

    According to the Arrhenius theory, a base is a substance that

    1. A Produces OH- ions in aqueous solution
    2. B Produces H+ ions in aqueous solution
    3. C Accepts protons only in non-aqueous solvents
    4. D Donates electron pairs only
    💡 Explanation:

    Arrhenius defined bases as substances that release OH- ions when dissolved in water.

  9. Q9 Past Paper · PPSC/FPSC/NTS easy

    According to the Bronsted-Lowry theory, an acid is defined as a

    1. A Proton acceptor
    2. B Electron pair donor
    3. C Proton donor
    4. D Electron pair acceptor
    💡 Explanation:

    Bronsted-Lowry theory broadens acids to any species that donates a proton.

  10. Q10 easy

    According to the Bronsted-Lowry theory, a base is defined as a

    1. A Proton donor
    2. B Proton acceptor
    3. C Electron pair acceptor
    4. D Substance producing OH- only
    💡 Explanation:

    Bronsted-Lowry theory defines a base as any species capable of accepting a proton.

  11. Q11 Past Paper · PPSC/FPSC/NTS easy

    According to the Lewis theory, a base is defined as a substance that

    1. A Donates a proton
    2. B Donates an electron pair
    3. C Accepts a proton
    4. D Produces H+ ions
    💡 Explanation:

    Lewis theory is the broadest definition, describing a base as an electron pair donor.

  12. Q12 easy

    According to the Lewis theory, an acid is defined as a substance that

    1. A Donates an electron pair
    2. B Produces OH- ions
    3. C Donates a proton only
    4. D Accepts an electron pair
    💡 Explanation:

    Lewis acids are defined as electron pair acceptors, extending beyond proton-based definitions.

  13. Q13 Past Paper · PPSC/FPSC/NTS easy

    The pH scale ranges from

    1. A 1 to 10
    2. B 0 to 14
    3. C 0 to 7
    4. D 7 to 14
    💡 Explanation:

    The conventional pH scale spans from 0 (most acidic) to 14 (most basic).

  14. Q14 easy

    A solution with pH less than 7 is

    1. A Acidic
    2. B Basic
    3. C Neutral
    4. D Amphoteric
    💡 Explanation:

    A pH value below 7 indicates an acidic solution.

  15. Q15 Past Paper · PPSC/FPSC/NTS easy

    A solution with pH greater than 7 is

    1. A Acidic
    2. B Basic
    3. C Neutral
    4. D Undefined
    💡 Explanation:

    A pH value above 7 indicates a basic (alkaline) solution.

  16. Q16 easy

    Pure water at 25°C has a pH of

    1. A 0
    2. B 7
    3. C 14
    4. D 1
    💡 Explanation:

    Pure water is neutral, with equal H+ and OH- concentrations, giving a pH of 7 at 25°C.

  17. Q17 medium

    pH is mathematically defined as

    1. A [H+] × 10
    2. B log[H+]
    3. C -log[H+]
    4. D 1/[H+]
    💡 Explanation:

    pH is defined as the negative base-10 logarithm of the hydrogen ion concentration.

  18. Q18 Past Paper · PPSC/FPSC/NTS medium

    The ionic product of water, Kw, at 25°C is

    1. A 1×10^-7
    2. B 1×10^0
    3. C 1×10^-14
    4. D 7×10^-14
    💡 Explanation:

    At 25°C, the ionic product of water Kw equals 1×10^-14.

  19. Q19 medium

    A strong acid is one that

    1. A Has a weak smell
    2. B Reacts slowly
    3. C Is always concentrated
    4. D Ionizes completely in aqueous solution
    💡 Explanation:

    Strong acids fully dissociate into ions when dissolved in water.

  20. Q20 Past Paper · PPSC/FPSC/NTS medium

    A weak acid is one that

    1. A Ionizes completely
    2. B Has no H+ ions
    3. C Ionizes only partially in aqueous solution
    4. D Is always dilute
    💡 Explanation:

    Weak acids only partially dissociate, establishing an equilibrium in solution.

  21. Q21 medium

    Which of the following is a strong acid

    1. A Hydrochloric acid (HCl)
    2. B Acetic acid (CH3COOH)
    3. C Carbonic acid (H2CO3)
    4. D Citric acid
    💡 Explanation:

    Hydrochloric acid fully ionizes in water, making it a strong acid.

  22. Q22 medium

    Which of the following is a weak acid

    1. A Acetic acid
    2. B Sulfuric acid
    3. C Nitric acid
    4. D Hydrochloric acid
    💡 Explanation:

    Acetic acid only partially dissociates in water, classifying it as a weak acid.

  23. Q23 Past Paper · PPSC/FPSC/NTS medium

    Which of the following is a strong base

    1. A Ammonium hydroxide
    2. B Sodium hydroxide (NaOH)
    3. C Aluminum hydroxide
    4. D Ferric hydroxide
    💡 Explanation:

    Sodium hydroxide fully dissociates in water, making it a strong base.

  24. Q24 medium

    Which of the following is a weak base

    1. A Sodium hydroxide
    2. B Potassium hydroxide
    3. C Calcium hydroxide
    4. D Ammonium hydroxide (NH4OH)
    💡 Explanation:

    Ammonium hydroxide only partially ionizes in water, classifying it as a weak base.

  25. Q25 medium

    A salt is formed by the reaction between

    1. A An acid and a base
    2. B Two acids
    3. C Two bases
    4. D Water and a metal only
    💡 Explanation:

    Neutralization of an acid with a base produces a salt and water.

  26. Q26 Past Paper · PPSC/FPSC/NTS medium

    A salt formed from a strong acid and a strong base is

    1. A Acidic
    2. B Basic
    3. C Amphoteric
    4. D Neutral
    💡 Explanation:

    Neither ion hydrolyzes significantly, so the resulting salt solution remains neutral.

  27. Q27 medium

    A salt formed from a strong acid and a weak base is

    1. A Basic
    2. B Neutral
    3. C Acidic
    4. D Amphoteric
    💡 Explanation:

    The conjugate acid of the weak base hydrolyzes in water, making the solution acidic.

  28. Q28 medium

    A salt formed from a weak acid and a strong base is

    1. A Acidic
    2. B Basic
    3. C Neutral
    4. D Amphoteric
    💡 Explanation:

    The conjugate base of the weak acid hydrolyzes in water, making the solution basic.

  29. Q29 Past Paper · PPSC/FPSC/NTS medium

    An amphoteric substance is one that can act as

    1. A Only an acid
    2. B Only a base
    3. C Neither an acid nor a base
    4. D Both an acid and a base
    💡 Explanation:

    Amphoteric substances can donate or accept protons, behaving as either an acid or a base.

  30. Q30 medium

    Which of the following oxides is amphoteric

    1. A Na2O
    2. B CO2
    3. C Al2O3
    4. D SO3
    💡 Explanation:

    Aluminum oxide reacts with both acids and bases, making it amphoteric.

  31. Q31 medium

    A buffer solution resists changes in

    1. A Volume
    2. B Color
    3. C Temperature
    4. D pH upon addition of small amounts of acid or base
    💡 Explanation:

    Buffer solutions maintain a nearly constant pH despite small additions of acid or base.

  32. Q32 Past Paper · PPSC/FPSC/NTS medium

    An acidic buffer is typically prepared from

    1. A A strong acid and its salt
    2. B A strong base and its salt
    3. C Two strong acids
    4. D A weak acid and its conjugate base (salt)
    💡 Explanation:

    Acidic buffers combine a weak acid with a salt of its conjugate base to resist pH changes.

  33. Q33 medium

    A basic buffer is typically prepared from

    1. A A strong base and a strong acid
    2. B A weak base and its conjugate acid (salt)
    3. C Two weak acids
    4. D Pure water
    💡 Explanation:

    Basic buffers combine a weak base with a salt of its conjugate acid.

  34. Q34 Past Paper · PPSC/FPSC/NTS medium

    Phenolphthalein indicator turns pink in

    1. A Acidic solutions
    2. B Neutral solutions
    3. C Basic solutions
    4. D All solutions equally
    💡 Explanation:

    Phenolphthalein remains colorless in acid and neutral solutions but turns pink in basic conditions.

  35. Q35 medium

    Methyl orange indicator turns red in

    1. A Basic solutions
    2. B Neutral solutions
    3. C Acidic solutions
    4. D All solutions equally
    💡 Explanation:

    Methyl orange turns red in strongly acidic solutions and yellow in basic ones.

  36. Q36 medium

    The process of adding an acid to a base (or vice versa) until the reaction is complete is called

    1. A Titration
    2. B Distillation
    3. C Filtration
    4. D Sublimation
    💡 Explanation:

    Titration is the controlled addition of one reactant to another to determine reaction completion.

  37. Q37 Past Paper · PPSC/FPSC/NTS medium

    The point in a titration where equal moles of acid and base have reacted is called the

    1. A pH point
    2. B Buffer point
    3. C Equivalence point
    4. D Boiling point
    💡 Explanation:

    The equivalence point marks where stoichiometrically equal amounts of acid and base have reacted.

  38. Q38 medium

    Table salt (sodium chloride) is chemically classified as

    1. A An acid
    2. B A neutral salt
    3. C A base
    4. D An oxide
    💡 Explanation:

    Sodium chloride, formed from a strong acid and strong base, is a neutral salt.

  39. Q39 medium

    Baking soda (sodium bicarbonate) reacts with acids to release

    1. A Carbon dioxide gas
    2. B Hydrogen gas
    3. C Oxygen gas
    4. D Nitrogen gas
    💡 Explanation:

    Sodium bicarbonate reacts with acids to produce carbon dioxide, water, and a salt.

  40. Q40 Past Paper · PPSC/FPSC/NTS medium

    Antacid tablets relieve acidity in the stomach because they contain

    1. A Strong acids
    2. B Sugar only
    3. C Neutral salts
    4. D Mild bases such as magnesium or aluminum hydroxide
    💡 Explanation:

    Antacids neutralize excess stomach acid using mild, safe bases.

  41. Q41 medium

    The strength of an acid is measured quantitatively by its

    1. A Molar mass
    2. B Boiling point
    3. C Dissociation (ionization) constant, Ka
    4. D Color intensity
    💡 Explanation:

    Ka quantifies how completely an acid dissociates in water, indicating its strength.

  42. Q42 medium

    A higher Ka value indicates a

    1. A Stronger acid
    2. B Weaker acid
    3. C Neutral solution
    4. D Basic solution
    💡 Explanation:

    A larger Ka value means greater dissociation, corresponding to a stronger acid.

  43. Q43 Past Paper · PPSC/FPSC/NTS hard

    pOH is related to pH by the equation

    1. A pH + pOH = 14
    2. B pH − pOH = 14
    3. C pH × pOH = 14
    4. D pH = pOH always
    💡 Explanation:

    At 25°C, pH and pOH always sum to 14 due to the water ionization constant.

  44. Q44 hard

    If a solution has a pH of 3, its pOH is

    1. A 11
    2. B 3
    3. C 7
    4. D 14
    💡 Explanation:

    Since pH + pOH = 14, a pH of 3 gives a pOH of 11.

  45. Q45 hard

    Universal indicator is used to

    1. A Measure temperature
    2. B Estimate the approximate pH of a solution using a color chart
    3. C Measure the molar mass
    4. D Detect the presence of metals only
    💡 Explanation:

    Universal indicator changes through a range of colors corresponding to different pH values.

  46. Q46 Past Paper · PPSC/FPSC/NTS hard

    Which of the following acids is found in vinegar

    1. A Citric acid
    2. B Formic acid
    3. C Lactic acid
    4. D Acetic acid
    💡 Explanation:

    Vinegar's sour taste and properties come from dissolved acetic acid.

  47. Q47 hard

    Which acid is found in citrus fruits like lemons

    1. A Citric acid
    2. B Acetic acid
    3. C Oxalic acid
    4. D Tartaric acid
    💡 Explanation:

    Citric acid is the primary organic acid responsible for the tartness of citrus fruits.

  48. Q48 hard

    Which acid is present in the human stomach and aids digestion

    1. A Sulfuric acid
    2. B Nitric acid
    3. C Hydrochloric acid
    4. D Acetic acid
    💡 Explanation:

    The stomach secretes hydrochloric acid to aid digestion and kill pathogens.

  49. Q49 Past Paper · PPSC/FPSC/NTS hard

    The salt formed when hydrochloric acid reacts with sodium hydroxide is

    1. A Sodium chloride
    2. B Sodium sulfate
    3. C Sodium nitrate
    4. D Sodium carbonate
    💡 Explanation:

    Neutralization of HCl with NaOH produces sodium chloride and water.

  50. Q50 hard

    Which of the following best describes a normal salt

    1. A Contains replaceable H+ or OH- ions
    2. B Formed from incomplete neutralization
    3. C Always acidic
    4. D Formed by the complete neutralization of an acid and base with no replaceable H or OH
    💡 Explanation:

    A normal salt results from complete neutralization, leaving no acidic hydrogen or basic hydroxide.

  51. Q51 hard

    An acid salt contains a replaceable

    1. A Metal ion
    2. B Hydrogen atom
    3. C Hydroxide ion only
    4. D Oxide ion
    💡 Explanation:

    Acid salts retain at least one ionizable hydrogen atom from the parent acid.

  52. Q52 hard

    Which of the following is an example of an acid salt

    1. A NaCl
    2. B Na2CO3
    3. C NaHCO3
    4. D CaCO3
    💡 Explanation:

    Sodium bicarbonate retains one replaceable hydrogen atom, making it an acid salt.

More Chemistry Topics

📖
Atomic Structure 50 MCQs
→ 📖
Periodic Table and Periodicity 50 MCQs
→ 📖
Chemical Bonding 50 MCQs
→ 📖
Stoichiometry and Chemical Calculations 50 MCQs
→ 📖
Gases and Gas Laws 50 MCQs
→ 📖
Thermochemistry 50 MCQs
→

See all Chemistry topics →

Get instant alerts & apply faster — install the free app Install App