Chemistry 9th Chap 10 : Topic 4 - Maryam Publications

Chemistry Chapter 10 : Topic 4

Acid and Base Dissociation

1 / 20

Which equation correctly represents the dissociation of hydrochloric acid in aqueous solution?

A) HCl(aq) → H₂+Cl₂

B) HCl(aq) ⇌ H₂O+Cl

C) HCl(aq) → H(aq)⁺ Cl(aq)⁻

D) HCl(g) → HCl(aq)

2 / 20

Which of the following correctly shows the dissociation of sodium hydroxide in water?

A) NaOH(aq) ⇌ NaOH(l)

B) NaOH(aq) → Na(aq)⁺+OH(aq)⁻

C) NaOH(aq) → Na+O+H

D) NaOH(aq) → Na⁺+O⁻+H⁺

3 / 20

What is the correct dissociation equation of sulfuric acid in the first step?

A) H₂SO₄ → H⁺+HSO₄⁻

B) H₂SO₄ → 2H⁺+SO₄²⁻

C) H₂SO₄ → H₂+SO₄

D) H₂SO₄ → 2H₂+SO₄²⁻

4 / 20

Which statement correctly describes aqueous ammonia (NH₄OH) dissociation?

A) NH₄OH does not ionize at all.

B) NH₄OH fully breaks into NH₄⁺ and OH⁻ ions.

C) NH₄OH produces H⁺ ions in water.

D) NH₄OH partially ionizes in water forming NH₄⁺ and OH⁻.

5 / 20

Which equation represents complete dissociation of calcium hydroxide?

A) Ca(OH)₂ → Ca⁺+OH₂

B) Ca(OH)₂ → Ca²⁺+2OH⁻

C) Ca(OH)₂ → Ca+O+H

D) Ca(OH)₂ → Ca²⁻+OH⁺

6 / 20

Which acid produces three hydrogen ions per molecule in aqueous solution?

A) H₃PO₄

B) H₂SO₄

C) HCl

D) HNO₃

7 / 20

What is the correct dissociation of nitric acid in water?

A) HNO₃ → H₃O+NO₃

B) HNO₃ → H⁺+NO₃⁻

C) HNO₃ → H₂+NO₃

D) HNO₃ → NO+H₂O

8 / 20

Why is water included in dissociation equations of acids?

A) It prevents ion formation.

B) It reacts chemically to form salts.

C) It reduces acidity completely.

D) It acts as a solvent and forms hydronium ions.

9 / 20

Which is the correct ionic form of a strong acid in water?

A) HCl → H+Cl (neutral atoms)

B) HCl → H₂+Cl₂

C) HCl → H₃O⁺+Cl⁻ (complete)

D) HCl ⇌ H⁺+Cl⁻ (partial)

10 / 20

Which of the following shows incorrect dissociation?

A) HNO₃ → H⁺+NO₃⁻

B) NaOH → Na⁺+OH⁻

C) KOH → K⁺+OH⁻

D) H₂SO₄ → H⁺+SO₄²⁻ (single step complete)

11 / 20

What ions are produced when potassium hydroxide dissolves in water?

A) K²⁺ and OH₂

B) K⁺ and OH⁻

C) K⁻ and OH⁺

D) K and OH (neutral atoms)

12 / 20

Which best represents a weak base dissociation?

A) Complete ionization into ions

B) No ion formation at all

C) Formation of covalent molecules only

D) Partial ionization in aqueous solution

13 / 20

What is the correct second step dissociation of H₂SO₄?

A) HSO₄⁻ → H₂O+SO₄²⁻

B) HSO₄⁻ → H₂+SO₄

C) HSO₄⁻ → H+SO₄⁻

D) HSO₄⁻ → H⁺+SO₄²⁻

14 / 20

Which statement best distinguishes acids in aqueous solution?

A) They form only salts in water.

B) They release metal ions only.

C) They release OH⁻ ions.

D) They release H⁺ / H₃O⁺ ions in water.

15 / 20

Which equation correctly shows dissociation of phosphoric acid (first step)?

A) H₃PO₄ → 3H⁺+PO₄³⁻

B) H₃PO₄ → H⁺+H₂PO₄⁻

C) H₃PO₄ → H₃+PO₄

D) H₃PO₄ → H₂+PO₄

16 / 20

Why are strong acids shown with single arrow ( →) in dissociation equations?

A) They partially ionize.

B) They completely ionize in water.

C) They form covalent bonds in solution.

D) They do not dissolve in water.

17 / 20

Which of the following correctly represents total ionic products of Ca(OH)₂?

A) Ca+OH₂

B) Ca²⁺+2OH⁻

C) Ca⁻+OH⁺

D) CaOH+OH

18 / 20

What happens to H⁺ ions in aqueous solution?

A) They remain free in solution.

B) They convert into oxygen gas.

C) They attach to water molecules forming H₃O⁺.

D) They form metallic bonds.

19 / 20

Which acid is diprotic and releases two H⁺ ions?

A) HNO₃

B) H₂SO₄

C) H₃PO₄

D) HCl

20 / 20

What is the key feature of dissociation equations in aqueous solutions?

A) They show nuclear reactions.

B) They show physical changes only.

C) They show formation of ions in water.

D) They show formation of gases only.

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