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🔥🌟 Grand Chemistry Interactive MCQs Quiz Test on Acids, Bases and Salts for Class FSC/MDCAT/ECAT Set I 🧪💡 | Learn & Practice!
1. H₂SO₄ is stronger acid than CH₃COOH because:
a) It gives two H⁺ ion per molecule
b) Its boiling point is high
c) Its degree of ionization is high
d) It is highly corrosive
✅ Correct Answer: (c)
The strength of an acid depends upon its degree of ionization and acid ionization constant (Kₐ). Greater the value of degree of ionization (equal or greater than 30%) and Kₐ (more than 10⁻³), stronger is the acid. The degree of ionization of H₂SO₄ is quite high about 60% (first step) and its Kₐ is also quite high about 10³ (Kₐ₂ for HSO₄⁻ = 1.3 x 10⁻²) showing that it is a very strong acid. Contrarily, The degree of ionization of CH₃COOH is quite low about 1.4% and its Ka is also quite low about 1.7 x 10⁻⁵ showing that it is a weaker acid than H₂SO₄.
The strength of an acid depends upon its degree of ionization and acid ionization constant (Kₐ). Greater the value of degree of ionization (equal or greater than 30%) and Kₐ (more than 10⁻³), stronger is the acid. The degree of ionization of H₂SO₄ is quite high about 60% (first step) and its Kₐ is also quite high about 10³ (Kₐ₂ for HSO₄⁻ = 1.3 x 10⁻²) showing that it is a very strong acid. Contrarily, The degree of ionization of CH₃COOH is quite low about 1.4% and its Ka is also quite low about 1.7 x 10⁻⁵ showing that it is a weaker acid than H₂SO₄.
2. Which of the following statements is not correct about the bases?
a) They have bitter tastes
b) They have high pH value
c) They react with acids to form salts
d) They turn blue litmus red
✅ Correct Answer: (d)
Bases turns red litmus paper blue.
Bases turns red litmus paper blue.
3. Al₂O₃ is amphoteric oxide because it reacts with:
a) Acids
b) neither acid nor base
c) Both acids and base
d) Base
✅ Correct Answer: (c)
👉Amphoteric oxides have dual characteristics of acid and base and hence they react both with acid and base through neutralization forming salt and water. 👉The oxides of amphoteric metals like Be, Al, Sn, Pb, Zn, Cr etc. are amphoteric . These oxides react with both acids and base via neutralization to form salt and water. 👉Al₂O₃, ZnO, BeO, SnO, SnO₂, PbO, PbO₂, Cr₂O₃ are amphoteric oxides.
👉Amphoteric oxides have dual characteristics of acid and base and hence they react both with acid and base through neutralization forming salt and water. 👉The oxides of amphoteric metals like Be, Al, Sn, Pb, Zn, Cr etc. are amphoteric . These oxides react with both acids and base via neutralization to form salt and water. 👉Al₂O₃, ZnO, BeO, SnO, SnO₂, PbO, PbO₂, Cr₂O₃ are amphoteric oxides.
4. Which of the following is not a buffer solution?
a) Na₂CO₃ /NaHCO₃
b) CH₃COOH/CH₃COONa
c) NH₄OH/NH₄Cl
d) NaOH/HCl
✅ Correct Answer: (d)
Buffer solution is a mixture of weak acid and its salt with strong base or weak base and its salt with strong base. In option ‘d’, NaOH and HCl are both base and acid.
Buffer solution is a mixture of weak acid and its salt with strong base or weak base and its salt with strong base. In option ‘d’, NaOH and HCl are both base and acid.
5. Which oxide is amphoteric in nature:
a) K₂O
b) CO₂
c) Al₂O₃
d) CaO
✅ Correct Answer: (c)
👉The oxides of amphoteric metals like Be, Al, Sn, Pb, Zn, Cr etc are amphoteric . These oxides react with both acids and base via neutralization to form salt and water. Al₂O₃, ZnO, BeO, SnO, SnO₂, PbO, PbO₂, Cr₂O₃ are amphoteric oxides. 👉The oxides of metals like K₂O, Li₂O, Na₂O, MgO, CaO, BaO etc. are basic. 👉The oxides of non-metals like CO₂, SO₂, SO₃, NO₂, N₂O₂, P₂O₃, P₂O₅, Cl₂O, Cl₂O₇ etc. are acidic. (Some non-metallic oxides like H₂O, N₂O, NO and CO are neutral).
👉The oxides of amphoteric metals like Be, Al, Sn, Pb, Zn, Cr etc are amphoteric . These oxides react with both acids and base via neutralization to form salt and water. Al₂O₃, ZnO, BeO, SnO, SnO₂, PbO, PbO₂, Cr₂O₃ are amphoteric oxides. 👉The oxides of metals like K₂O, Li₂O, Na₂O, MgO, CaO, BaO etc. are basic. 👉The oxides of non-metals like CO₂, SO₂, SO₃, NO₂, N₂O₂, P₂O₃, P₂O₅, Cl₂O, Cl₂O₇ etc. are acidic. (Some non-metallic oxides like H₂O, N₂O, NO and CO are neutral).
6. Which of the following does not alter the pH of a solution?
a) NH₄Cl
b) Na₂CO₃
c) NaCl
d) Mg(OH)Cl
✅ Correct Answer: (c)
Neutral salts formed from strong acids and strong bases like NaCl, KBr, KCl, BaCl₂, Na₂SO₄, KNO₃ etc. do not change the pH of solution.
Neutral salts formed from strong acids and strong bases like NaCl, KBr, KCl, BaCl₂, Na₂SO₄, KNO₃ etc. do not change the pH of solution.
7. Conjugated acids of NH₃ is:
a) NH₄⁺
b) NH₂⁻
c) NH₂
d) NH
✅ Correct Answer: (a)
👉To form conjugate acid from a compound or ion, just add H into it while to form conjugate base of a compound or ion just remove H from it. Don’t forget to balance charge either adding or subtracting H. 👉Addition of H increases one unit + charge while removing of H decreases one + charge. 👉NH₃ (adding add H into it will introduce + charge) …………… NH₄⁺ (conjugate acid) 👉NH₃ (removing H from it will introduce – charge) ……………. NH₂⁻ (conjugate base)
👉To form conjugate acid from a compound or ion, just add H into it while to form conjugate base of a compound or ion just remove H from it. Don’t forget to balance charge either adding or subtracting H. 👉Addition of H increases one unit + charge while removing of H decreases one + charge. 👉NH₃ (adding add H into it will introduce + charge) …………… NH₄⁺ (conjugate acid) 👉NH₃ (removing H from it will introduce – charge) ……………. NH₂⁻ (conjugate base)
8. Salt which is formed by the neutralization of weak acid and strong base is:
a) NaNO₃
b) NH₄Cl
c) Na₂CO₃
d) NH₄CN
✅ Correct Answer: (c)
👉Strong bases contain Na⁺, K⁺, Ba²⁺ as cation while weak acids contains anions other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. 👉A salt formed from weak acid and strong base via neutralization contains any one of the cation like Na⁺, K⁺, Ba²⁺ and anion other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. 👉Sodium carbonate (Na₂CO₃) is a salt derived from the neutralization of weak acid (H₂CO₃ containing CO₃²⁻ anion) and strong base (NaOH).
👉Strong bases contain Na⁺, K⁺, Ba²⁺ as cation while weak acids contains anions other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. 👉A salt formed from weak acid and strong base via neutralization contains any one of the cation like Na⁺, K⁺, Ba²⁺ and anion other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. 👉Sodium carbonate (Na₂CO₃) is a salt derived from the neutralization of weak acid (H₂CO₃ containing CO₃²⁻ anion) and strong base (NaOH).
9. A conjugate acid base pair has the difference of only:
a) One electron
b) One proton
c) One electron pair
d) One proton pair
✅ Correct Answer: (b)
👉Conjugate acid-base pair differs from one another only by a single proton (H⁺). 👉To identify a conjugate acid base pair, we look at the specie that donates a proton and the specie that is formed from it by the loss of proton. 👉In the given reaction between HCl and NH₃, NH₃ accepts a proton acting as a Bronsted base to form NH₄⁺ which is its conjugate acid. Similarly, HCl donates a proton acting as a Bronsted acid to form Cl⁻ which is its conjugate base.
👉Conjugate acid-base pair differs from one another only by a single proton (H⁺). 👉To identify a conjugate acid base pair, we look at the specie that donates a proton and the specie that is formed from it by the loss of proton. 👉In the given reaction between HCl and NH₃, NH₃ accepts a proton acting as a Bronsted base to form NH₄⁺ which is its conjugate acid. Similarly, HCl donates a proton acting as a Bronsted acid to form Cl⁻ which is its conjugate base.
10. Salt formed by neutralization of weak acid and weak base is:
a) NH₄Cl
b) Na₂CO₃
c) NH₄CN
d) Na₂SO₄
✅ Correct Answer: (c)
Strong bases contain Na⁺, K⁺, Ba²⁺ as cation while weak acids contains anions other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. A salt formed from weak acid and weak base via neutralization contains any cation other Na⁺, K⁺, Ba²⁺ and any anion other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. Ammonium cyanide (NH₄CN) is a salt derived from the neutralization of weak acid (HCN containing CN⁻ anion) and weak base (NH₄OH).
Strong bases contain Na⁺, K⁺, Ba²⁺ as cation while weak acids contains anions other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. A salt formed from weak acid and weak base via neutralization contains any cation other Na⁺, K⁺, Ba²⁺ and any anion other than Cl⁻, Br⁻, I⁻, NO₃⁻, SO₄²⁻, ClO₄⁻, and ClO₃⁻. Ammonium cyanide (NH₄CN) is a salt derived from the neutralization of weak acid (HCN containing CN⁻ anion) and weak base (NH₄OH).
11. The aqueous solution of KCl is:
a) Neutral
b) Acidic
c) Basic
d) Alkaline
✅ Correct Answer: (a)
✨KCl is a salt formed from a strong acid (HCl) and a strong base (KOH). ✨Salts of strong acid + strong base do not hydrolyze in water as neither cation (K⁺) nor anion (Cl⁻) reacts with water, therefore, no extra H⁺ or OH⁻ ions are produced. ✨Thus, solution remains at pH ≈ 7 and the aqueous solution of KCl is neutral.
✨KCl is a salt formed from a strong acid (HCl) and a strong base (KOH). ✨Salts of strong acid + strong base do not hydrolyze in water as neither cation (K⁺) nor anion (Cl⁻) reacts with water, therefore, no extra H⁺ or OH⁻ ions are produced. ✨Thus, solution remains at pH ≈ 7 and the aqueous solution of KCl is neutral.
12. Which one of the following yield basic solution?
a) Copper sulphate
b) Ammonium chloride
c) Soda acetate
d) Sliver nitrate
✅ Correct Answer: (c)
👉 Sodium acetate is the salt of a strong base (NaOH) and a weak acid (CH₃COOH). Such salts undergo hydrolysis to produce OH⁻ ions, giving a basic solution. 👉 All other Salts are the salts of weak bases and strong acids which undergo hydrolysis to produce H⁺ ions, giving acidic solution.
👉 Sodium acetate is the salt of a strong base (NaOH) and a weak acid (CH₃COOH). Such salts undergo hydrolysis to produce OH⁻ ions, giving a basic solution. 👉 All other Salts are the salts of weak bases and strong acids which undergo hydrolysis to produce H⁺ ions, giving acidic solution.
13. Universal indicator turns red in:
a) Neutral solution
b) Alkaline solution
c) Acid solution
d) Basic solution
✅ Correct Answer: (c) Acid solution
👉 Universal indicator shows red in strongly acidic solutions (low pH ≈ 1–3). 🔎 In Weakly acidic solution (pH 4–6), Universal indicator shows orange/yellow. 🔎 Neutral (pH 7) → green. Weakly basic (pH 8–11) → blue. 🔎 Strongly basic (pH 12–14) → violet/purple.
👉 Universal indicator shows red in strongly acidic solutions (low pH ≈ 1–3). 🔎 In Weakly acidic solution (pH 4–6), Universal indicator shows orange/yellow. 🔎 Neutral (pH 7) → green. Weakly basic (pH 8–11) → blue. 🔎 Strongly basic (pH 12–14) → violet/purple.
14. Which one of the following is NOT a strong acid?
a) HF
b) HNO₃
c) HCl
d) H₂SO₄
✅ Correct Answer: (a) HF
🔎 HF is not a strong acid because it does not fully dissociate in aqueous solution, unlike HCl, HNO₃, and H₂SO₄ which are strong acids.
🔎 HF is not a strong acid because it does not fully dissociate in aqueous solution, unlike HCl, HNO₃, and H₂SO₄ which are strong acids.
15. Which one of the following substances has pH value more than 7?
a) Vinegar
b) Sodium carbonate
c) Sulphuric acid
d) Soda water
✅ Correct Answer: (b) Sodium carbonate
🔎 Sodium carbonate is a Salt of strong base (NaOH) and weak acid (H₂CO₃) which hydrolyzes to give OH⁻ ions making the solution having pH greater than 7.
🔎 Sodium carbonate is a Salt of strong base (NaOH) and weak acid (H₂CO₃) which hydrolyzes to give OH⁻ ions making the solution having pH greater than 7.
16. Which one of the following is NOT a salt of weak acids and strong bases?
a) Sodium ethanoate
b) Potassium cyanide
c) Ammonium chloride
d) Sodium carbonate
✅ (c) Ammonium chloride
🔎 Ammonium chloride is the salt of a weak base (NH₃) and a strong acid (HCl), not of a weak acid and strong base.
🔎 Ammonium chloride is the salt of a weak base (NH₃) and a strong acid (HCl), not of a weak acid and strong base.
17. Which one of the following is not a salt of strong acids and weak bases?
a) Copper(II) sulphate
b) Sodium acetate
c) Ammonium chloride
d) Ferric chloride
✅ Correct Answer: (b)
🔎 Sodium acetate is the salt of a strong base (NaOH) and a weak acid (CH₃COOH), so it does not belong to the category of salts formed from strong acids and weak bases.
🔎 Sodium acetate is the salt of a strong base (NaOH) and a weak acid (CH₃COOH), so it does not belong to the category of salts formed from strong acids and weak bases.
18. Which one of the following salts dissolves in water to produce a solution with pH less than 7?
a) Sodium ethanoate
b) Borax
c) Bleach
d) None of them
✅ Correct Answer: (d) None of them
🔎 All given salts (sodium ethanoate → CH₃COONa, borax → Na₂B₄O₇, bleach → NaOCl) are salts of astrong base + weak acid, so they hydrolyze to give basic solutions (pH > 7). Therefore, none of them produces a solution with pH less than 7.
🔎 All given salts (sodium ethanoate → CH₃COONa, borax → Na₂B₄O₇, bleach → NaOCl) are salts of astrong base + weak acid, so they hydrolyze to give basic solutions (pH > 7). Therefore, none of them produces a solution with pH less than 7.
19. Which one of the following salts dissolves in water to produce a solution with pH more than 7?
a) Ammonium nitrate
b) Ferric chloride
c) Sodium sulphate
d) None of them
✅ Correct Answer: (d) None of them
🔎 All listed salts either give acidic [Ammonium nitrate (NH₄NO₃) Ferric chloride (FeCl₃)]or neutral [Sodium sulphate (Na₂SO₄)] solutions. None of them hydrolyzes to produce OH⁻ ions, so none yields a solution with pH > 7. Since none of the given salts produces a basic solution, the correct choice is None of them. ✅
🔎 All listed salts either give acidic [Ammonium nitrate (NH₄NO₃) Ferric chloride (FeCl₃)]or neutral [Sodium sulphate (Na₂SO₄)] solutions. None of them hydrolyzes to produce OH⁻ ions, so none yields a solution with pH > 7. Since none of the given salts produces a basic solution, the correct choice is None of them. ✅
20. Which of the following salts has no water of crystallization?
a) Gypsum
b) Blue vitriol
c) Baking soda
d) Washing soda
✅ Correct Answer: (c) Baking soda
🔎 Gypsum (CaSO₄·2H₂O) Contains 2 molecules of water of crystallization. 🔎 Blue vitriol (CuSO₄·5H₂O) Contains 5 molecules of water of crystallization. 🔎 Washing soda (Na₂CO₃·10H₂O) Contains 10 molecules of water of crystallization. 👉 Baking soda (NaHCO₃) is an anhydrous salt and does not contain water of crystallization, unlike gypsum, blue vitriol, and washing soda which all have definite numbers of water molecules in their crystal structure.
🔎 Gypsum (CaSO₄·2H₂O) Contains 2 molecules of water of crystallization. 🔎 Blue vitriol (CuSO₄·5H₂O) Contains 5 molecules of water of crystallization. 🔎 Washing soda (Na₂CO₃·10H₂O) Contains 10 molecules of water of crystallization. 👉 Baking soda (NaHCO₃) is an anhydrous salt and does not contain water of crystallization, unlike gypsum, blue vitriol, and washing soda which all have definite numbers of water molecules in their crystal structure.
21. Which ion is not present in dilute sulfuric acid?
a) H⁺
b) OH⁻
c) SO₃²⁻
d) SO₄²⁻
✅ Correct Answer: (c) SO₃²⁻
🔎 Dilute sulfuric acid (H₂SO₄ in water) being a Strong acid → completely ionizes to produces H⁺ (or H₃O⁺) ions and SO₄²⁻ ions. OH⁻ ions are present in water at very low concentration due to water autoionization, but in acidic solution they are suppressed. Still, trace OH⁻ always exists due to water autoionization. ✅ (though negligible compared to H⁺). 👉 SO₃²⁻ ions (sulfite) come from H₂SO₃ (sulfurous acid), not from H₂SO₄. Therefore, SO₃²⁻ is not present in dilute sulfuric acid. ✨ Short Reason: 🔎 Dilute H₂SO₄ contains H⁺ and SO₄²⁻ ions. Trace OH⁻ ions exist due to water autoionization. But SO₃²⁻ ions belong to sulfurous acid, not sulfuric acid, so they are absent.
🔎 Dilute sulfuric acid (H₂SO₄ in water) being a Strong acid → completely ionizes to produces H⁺ (or H₃O⁺) ions and SO₄²⁻ ions. OH⁻ ions are present in water at very low concentration due to water autoionization, but in acidic solution they are suppressed. Still, trace OH⁻ always exists due to water autoionization. ✅ (though negligible compared to H⁺). 👉 SO₃²⁻ ions (sulfite) come from H₂SO₃ (sulfurous acid), not from H₂SO₄. Therefore, SO₃²⁻ is not present in dilute sulfuric acid. ✨ Short Reason: 🔎 Dilute H₂SO₄ contains H⁺ and SO₄²⁻ ions. Trace OH⁻ ions exist due to water autoionization. But SO₃²⁻ ions belong to sulfurous acid, not sulfuric acid, so they are absent.
22. Which salt is NOT derived from a strong acid and a strong soluble base?
a) MgCl₂
b) LiClO₄
c) NaI
d) CsBr
✅ Correct Answer: (a)
Magnesium chloride is formed from HCl (strong acid) and Mg(OH)₂ (weak, sparingly soluble base). Therefore, it is not a salt of strong acid and strong soluble base, unlike LiClO₄, NaI, and CsBr.
Magnesium chloride is formed from HCl (strong acid) and Mg(OH)₂ (weak, sparingly soluble base). Therefore, it is not a salt of strong acid and strong soluble base, unlike LiClO₄, NaI, and CsBr.
23. A Bronsted-Lowry base is defined as:
a) a hydroxide acceptor
b) an electron pair acceptor
c) a proton acceptor
d) a hydroxide donor
✅ Correct Answer: (c) a proton acceptor
According to Bronsted–Lowry concept, a base is a proton (H⁺) acceptor, while an acid is a proton donor.
According to Bronsted–Lowry concept, a base is a proton (H⁺) acceptor, while an acid is a proton donor.
24. Which one of the following yield basic solution?
a) Copper sulphate
b) Ammonium chloride
c) Potassium cyanide
d) Sliver nitrate
✅ Correct Answer: (c) Potassium cyanide
Potassium cyanide is formed from a strong base (KOH) and a weak acid (HCN). Such salts hydrolyze to produce OH⁻ ions, giving a basic solution.
Potassium cyanide is formed from a strong base (KOH) and a weak acid (HCN). Such salts hydrolyze to produce OH⁻ ions, giving a basic solution.
25. Universal indicator turns green in:
a) Neutral solution
b) Alkaline solution
c) Acid solution
d) Basic solution
✅ Correct Answer: (a)Neutral solution
👉 Universal indicator shows red in strongly acidic solutions (low pH ≈ 1–3). 👉 In Weakly acidic solution (pH 4–6), Universal indicator shows orange/yellow. 👉 Neutral (pH 7) → green. Weakly basic (pH 8–11) → blue. 👉 Strongly basic (pH 12–14) → violet/purple.
👉 Universal indicator shows red in strongly acidic solutions (low pH ≈ 1–3). 👉 In Weakly acidic solution (pH 4–6), Universal indicator shows orange/yellow. 👉 Neutral (pH 7) → green. Weakly basic (pH 8–11) → blue. 👉 Strongly basic (pH 12–14) → violet/purple.
26. NH₃ can be a base according to
a) Arrhenius theory
b) Bronsted-Lowry theory
c) Lewis theory
d) both b and c
✅ Correct Answer: (d) both b and c
👉 NH₃ acts as a proton acceptor (Bronsted–Lowry base) and as an electron pair donor (Lewis base). 👉 NH₃ does not contain OH⁻, but it reacts with water to produce OH⁻ indirectly (NH₃ +H₂O ⇌ NH₄⁺ + OH⁻). So NH₃ is not a direct Arrhenius base, but often considered borderline.
👉 NH₃ acts as a proton acceptor (Bronsted–Lowry base) and as an electron pair donor (Lewis base). 👉 NH₃ does not contain OH⁻, but it reacts with water to produce OH⁻ indirectly (NH₃ +H₂O ⇌ NH₄⁺ + OH⁻). So NH₃ is not a direct Arrhenius base, but often considered borderline.
27. Which of the following is a Lewis base?
a) HNO₃
b) CN⁻
c) HCl
d) AlCl₃
✅ Correct Answer: (b) CN⁻
All anions with lone pairs on the central atom (usually N, P, O, S, Cl, Br, I etc.)act as a Lewis base. The cyanide ion (CN⁻) has a lone pair of electrons that it can donate, making it a Lewis base.
All anions with lone pairs on the central atom (usually N, P, O, S, Cl, Br, I etc.)act as a Lewis base. The cyanide ion (CN⁻) has a lone pair of electrons that it can donate, making it a Lewis base.
28. A substance that can donate a pair of electrons to form coordinate covalent bond
a) Lewis base
b) Bronsted-Lowry acid
c) Bronsted-Lowry base
d) Arrhenius base
✅ Correct Answer: (a) Lewis base
A Lewis base donates a pair of electrons to form a coordinate covalent bond, while a Lewis acid accepts them.
A Lewis base donates a pair of electrons to form a coordinate covalent bond, while a Lewis acid accepts them.
29. If pH value is greater than 7, then solution is
a) acidic
b) basic
c) amphoteric
d) neutral
✅ Correct Answer: (b) basic
(a) ⚡pH < 7 → acidic solution. ⚡pH = 7 → neutral solution. ⚡pH > 7 → basic/alkaline solution. ✨A solution with pH greater than 7 is basic (alkaline) because it has excess OH⁻ ions compared to H⁺ ions.
(a) ⚡pH < 7 → acidic solution. ⚡pH = 7 → neutral solution. ⚡pH > 7 → basic/alkaline solution. ✨A solution with pH greater than 7 is basic (alkaline) because it has excess OH⁻ ions compared to H⁺ ions.
30. Which of the following is an acid–base conjugate pair?
a) HClO and Cl⁻
b) HNO₂ and NO₃⁻
c) H₂CO₃ and CO₃²⁻
d) HF and F⁻
✅ Correct Answer: (d) HF and F⁻
✨A conjugate acid–base pair differs by one proton (H⁺). ⚡Acid → loses H⁺ → conjugate base. ⚡Base → gains H⁺ → conjugate acid.⚡HF → F⁻ (acid loses 1 proton) is a valid acid–base conjugate pair. ✨ (A conjugate acid–base pair must differ by exactly one proton. H₂CO₃’s immediate conjugate base is HCO₃⁻; CO₃²⁻ is two protons away, so H₂CO₃/CO₃²⁻ is not a conjugate pair).
✨A conjugate acid–base pair differs by one proton (H⁺). ⚡Acid → loses H⁺ → conjugate base. ⚡Base → gains H⁺ → conjugate acid.⚡HF → F⁻ (acid loses 1 proton) is a valid acid–base conjugate pair. ✨ (A conjugate acid–base pair must differ by exactly one proton. H₂CO₃’s immediate conjugate base is HCO₃⁻; CO₃²⁻ is two protons away, so H₂CO₃/CO₃²⁻ is not a conjugate pair).
31. What will be the pH of aqueous solution of NH₄Cl?
a) pH = 7
b) pH = 0
c) pH > 7
d) pH < 7
✅ Correct Answer: (d) pH < 7
✨Salts of weak base + strong acid undergo cationic hydrolysis to give acidic solution. NH₄Cl Formed from weak base (NH₃) + strong acid (HCl). ✨NH₄Cl ionizes to give netural Cl⁻(from strong acid) and NH₄⁺ ion (from weak base) which hydrolyzes to produce H₃O⁺ or H⁺ ions, lowering pH making the solution acidic (NH₄⁺ + H₂O → NH₄OH + H⁺)
✨Salts of weak base + strong acid undergo cationic hydrolysis to give acidic solution. NH₄Cl Formed from weak base (NH₃) + strong acid (HCl). ✨NH₄Cl ionizes to give netural Cl⁻(from strong acid) and NH₄⁺ ion (from weak base) which hydrolyzes to produce H₃O⁺ or H⁺ ions, lowering pH making the solution acidic (NH₄⁺ + H₂O → NH₄OH + H⁺)
32. Which one of the following is non-hydrolyzable salt?
a) Na₂CO₃
b) NaCl
c) AlCl₃
d) CuSO₄
✅ Correct Answer: (b) NaCl
✨NaCl is formed from a strong acid (HCl) and a strong base (NaOH). Such salts are non hydrolyzable and give a neutral solution (pH ≈ 7).
✨NaCl is formed from a strong acid (HCl) and a strong base (NaOH). Such salts are non hydrolyzable and give a neutral solution (pH ≈ 7).
33. Aqueous solution of KCl has a pH approximately equal to that of aqueous solution of
a) NaNO₃
b) Cu(NO₃)₂
c) NH₄NO₃
d) Al(NO₃)₃
✅ Correct Answer: (a)
✨KCl is formed from a strong acid (HCl) and a strong base (KOH). ✨Salts of strong acid with strong base are non hydrolyzable and give a neutral solution (pH ≈ 7). ✨NaCl is formed from a strong acid (HCl) and a strong base (NaOH).
✨KCl is formed from a strong acid (HCl) and a strong base (KOH). ✨Salts of strong acid with strong base are non hydrolyzable and give a neutral solution (pH ≈ 7). ✨NaCl is formed from a strong acid (HCl) and a strong base (NaOH).
34. Hydrolysis of potassium acetate gives
a) Basic solution
b) Highly acidic solution
c) Neutral solution
d) Acidic solution Explanation
✅ Correct Answer: (a)
Potassium acetate is formed from a strong base (KOH) and a weak acid (CH₃COOH). Such salts hydrolyze to produce OH⁻ ions, giving a basic solution.
Potassium acetate is formed from a strong base (KOH) and a weak acid (CH₃COOH). Such salts hydrolyze to produce OH⁻ ions, giving a basic solution.
Aqueous solution of CuSO₄ has a pH
a) Greater than 7
b) Less than 7
c) Equal to 7
d) Zero
✅ Correct Answer: (b)
Salts of weak base + strong acid undergo cationic hydrolysis to give acidic solution. CuSO₄ is formed from weak base (Cu(OH)₂) + strong acid (H₂SO₄). CuSO₄ ionizes to give neutral SO₄²⁻ (from strong acid) and Cu²⁺ ion (from weak base) which hydrolyzes to produce H₃O⁺ or H⁺ ions, lowering pH making the solution acidic (Cu²⁺ + 2H₂O → Cu(OH)₂ + 2H⁺).
Salts of weak base + strong acid undergo cationic hydrolysis to give acidic solution. CuSO₄ is formed from weak base (Cu(OH)₂) + strong acid (H₂SO₄). CuSO₄ ionizes to give neutral SO₄²⁻ (from strong acid) and Cu²⁺ ion (from weak base) which hydrolyzes to produce H₃O⁺ or H⁺ ions, lowering pH making the solution acidic (Cu²⁺ + 2H₂O → Cu(OH)₂ + 2H⁺).
36. Which of the following phenomena will occur when a small amount of acid is added to water?
a) Dilution
b) Neutralization
c) Ionization
d) Both a and c
✅ Correct Answer: (d)
When acid is added to water, it gets diluted and simultaneously ionizes to release H⁺ ions. Neutralization does not occur because no base is present. Since both dilution and ionization occur, the correct choice is (d).
When acid is added to water, it gets diluted and simultaneously ionizes to release H⁺ ions. Neutralization does not occur because no base is present. Since both dilution and ionization occur, the correct choice is (d).
37. Strong bases are
a) Non-electrolytes
b) Strong electrolytes
c) Weak electrolytes
d) also strong acids
✅ Correct Answer: (b)
Strong bases dissociate completely in water, producing OH⁻ ions and making them strong electrolytes.
Strong bases dissociate completely in water, producing OH⁻ ions and making them strong electrolytes.
38. Whose definition of acids and bases emphasizes the role of protons?
a) Faraday
b) Arrhenius
c) Brønsted & Lowry
d) Lewis
✅ Correct Answer: (c)
The Brønsted–Lowry definition emphasizes proton transfer: acids donate protons, bases accept protons.
The Brønsted–Lowry definition emphasizes proton transfer: acids donate protons, bases accept protons.
39. An electron-pair acceptor is a
a) Lewis base
b) Traditional acid
c) Lewis acid
d) Brønsted base
✅ Correct Answer: (c)
By definition, a Lewis acid is an electron pair acceptor, while a Lewis base is an electron pair donor.
By definition, a Lewis acid is an electron pair acceptor, while a Lewis base is an electron pair donor.
40. Which one of the given is hydracid?
a) HNO₃
b) HCN
c) H₂SO₄
d) H₃PO₄
✅ Correct Answer: (b) HCN
Hydracids are acids composed of hydrogen + a non metal element (without oxygen). Examples: HCl, HBr, HI, HCN.
Hydracids are acids composed of hydrogen + a non metal element (without oxygen). Examples: HCl, HBr, HI, HCN.
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Aptitude test (MDCAT/ECAT)
Bases and Salts
Bases and Salts MCQs
Bases and Salts Quiz
ECAT Chemistry
First year
High-Yield Acids
MDCAT Acids
MDCAT ECAT FSC Chemistry Acids