Model Test Questions Class 10 Chemistry Test #3 for Chapter # 2 (Acids, Bases and Salts)|Updated 2026-27 (SLO)

📘 Model Test Questions Class 10 Chemistry Test # 3 for Chapter # 2 (Acids, Bases and Salts)

(Three Concepts of acids, bases, pH, pOH, Kw, Salts, its types, preparation and uses, Buffers)

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📘 Short Answer-Questions (SLO based)

Prepared by Inam Jazbi – Learn Chemistry

Q1.

What is Bronsted-Lowery acid-base theory? Define Bronsted-Lowry base and explain with an example that water is a Bronsted-Lowry base.

Q2.

What are conjugate acid-base pairs? Explain with examples. Differentiate between proton transfer and electron pair transfer in acid-base reactions.

Q3.

Classify the following solutions as acidic, basic or neutral (i) A solution that has [H⁺] = 1 x 10⁻⁴ mol.dm⁻³ (acidic as [H⁺] > 1 x 10⁻⁷ mol.dm⁻³) (ii) A solution that has [H⁺] = 1 x 10⁻¹¹ mol.dm⁻³ (basic as [H⁺] < 1 x 10⁻⁷ mol.dm⁻³) (iii) A solution that has [H⁺] = 1 x 10⁻⁹ mol.dm⁻³ (basic as [H⁺] < 1 x 10⁻⁷ mol.dm⁻³) (iv) A solution that has [H⁺] = 1 x 10⁻³ mol.dm⁻³ (acidic as [H⁺] > 1 x 10⁻⁷ mol.dm⁻³)

Q4.

Elaborate the ionization equation of water. Explain in detail that how water ionization is related with pH of solution? Explain the relationship between Kw, pH, and pOH.

Q5.

Define the following terms: (a) pH (b) Indicator (c) Neutralization (d) Titration (e) Normal salt (f) Basic salt

Q6.

Define buffers. What is the composition of buffers? Discuss its importance in our daily life.

Q7.

Classify a solution with pH = 3, 7, and 10. Name three common household substances having a. pH value greater than 7 (Bitter-gourd, coffee and chocolate) b. pH value less than 7 (curd, vinegar, lemon and orange) c. pH value equal to 7 (sugar, common salt, pure water)

Q8.

Name the acids present in: i. Vinegar (acetic acid) ii. Ant sting (formic acid) iii. Citrus fruit (citric acid) iv. Sour milk (lactic acid)

Q9.

What are conjugate bases of each of the following? HS⁻, H₃O⁺, H₂PO₄⁻, HSO₄⁻, HF, CH₃COOH, [Al(H₂O)₆]³⁺

Q10.

Give the conjugate acids of the following: OH⁻, HCO₃⁻, HPO₄²⁻, CH₃NH₂, CO₃²⁻, CH₃COO⁻

Q11.

Which of the following behave both as Bronsted acids and Bronsted bases? H₂O, HCO₃⁻, H₂SO₄, H₃PO₄, HS⁻

Q12.

What do you mean by neutralization reaction according to Arrhenius acid-base concept? What do you mean by balancing of neutralization reaction with the help of examples?

Q13.

You are having a strong acid (HNO₃) and strong base (NaOH) on mixing i. What type of salt you will have? ii. What type of reaction will it be? iii. Will it be soluble or insoluble salt? iv. If it is soluble, how will it be recovered?

Q14.

Give brief answers of following: (i). Why pure water is not a strong electrolyte? (ii). Why ionic-product constant of water is temperature dependent? (iii). Define a base and explain that all alkalis are bases, but all bases are not alkalis. (iv). Which kind of bond is formed between Lewis acid and a base? Name the product formed between them (v). Why H⁺ ion acts as a Lewis acid? (vi). Name two acids used in the manufacture of fertilizers. (vii).Write the chemical formulae and the names of three Arrhenius acid and bases (viii).What do you mean by neutralization reaction according to Arrhenius acid-base concept? (ix).Prove that water is an amphoteric specie. (x). Identify the acid and base in the reaction: HCl + H₂O → H₃O⁺ + Cl⁻ (using Brønsted–Lowry concept). (xi). Classify NH₃ as an acid or base under all three concepts. (xii). Give one example where a substance acts as a Lewis acid and a Lewis base. (xiii). Show that pure water is neutral using Kw. (xiv). How does temperature affect the value of Kw? (xv). Explain why carbon dioxide gas is released in some salt preparations. (xvi). Write chemical equations for salt preparation by: ✨Acid + Base ✨ Acid + Metal ✨ Acid + Carbonate (xvii). Why is the pH of blood important to maintain? Or Why is maintaining pH important in biological systems? (xviii). A substance does not produce H⁺ ions in water but still behaves as an acid. Explain this using the Lewis concept. (xix). Analyze a reaction where a substance behaves as both acid and base (amphoteric behavior).

📘 Long Questions (SLO based)

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Q1.

Describe salts, preparation of salts and types of salts.

Q2.

State and explain Lewis concept of acids and bases with two examples. Explain why the Lewis concept is more general than the other two.

Q3.

Discuss in detail how different solutions in aqueous system exhibit increase in acidity and increase in basicity on the basis of H⁺ and OH⁻?

Q4.

Write down the uses of salt in daily life.

Q5.

Elaborate the Arrhenius concept of acid and base with suitable examples. Why is the Arrhenius concept limited compared to Brønsted–Lowry theory? Which of the following is/are Arrhenius acids and bases? (a) Ca(OH)₂ (b) HNO₃ (c) NaOH (d) H₂SO₄ (e) KOH

Q6.

A solution of HCl has pH of 2.3. Calculate its pOH and [H⁺]?

Q7.

Find pH, pOH, [OH⁻] and [H⁺] of 2.46 x 10⁻⁹ M KOH solution.

📘 Multiple Choice Questions (MCQs) of Acids bases and salts from Text Book (Click to Reveal Answer)

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1. Corrosive effect on skin is caused by

🟥 (a) Acid

🟦 (b) Base

🟩 (c) Salt

🟨 (d) Both a and b

✔ Correct Answer: 🟨 (d)
Reason: Both strong acids and strong bases are corrosive and can damage skin tissues.

2. Preservatives are used to preserve

🟥 (a) Acid

🟦 (b) Base

🟩 (c) Food

🟨 (d) Water

✔ Correct Answer: 🟩 (c)
Short Reason: Preservatives are added to prevent spoilage of food.

3. Which of the following is NOT an Arrhenius acid?

🟥 (a) HCl

🟦 (b) CO₂

🟩 (c) HNO₃

🟨 (d) H₂SO₄

✔ Correct Answer: 🟦 (b)
Short Reason: CO₂ is an acidic oxide, not an Arrhenius acid itself.

4. NH₃ can be a base according to

🟥 (a) Arrhenius theory

🟦 (b) Brønsted-Lowry theory

🟩 (c) Lewis theory

🟨 (d) both b and c

✔ Correct Answer: 🟨 (d)
Short Reason: NH₃ acts as a proton acceptor and electron pair donor.

5. Which of the following is a Lewis base?

🟥 (a) HNO₃

🟦 (b) CN⁻

🟩 (c) HCl

🟨 (d) AlCl₃

✔ Correct Answer: 🟦 (b)
Short Reason: CN⁻ donates an electron pair, so it acts as a Lewis base.

6. A substance that can donate a pair of electrons to form coordinate covalent bond

🟥 (a) Brønsted-Lowry base

🟦 (b) Brønsted-Lowry acid

🟩 (c) Lewis acid

🟨 (d) Lewis base

✔ Correct Answer: 🟨 (d)
Short Reason: Lewis base donates an electron pair to form a coordinate bond.

7. If pH value is greater than 7, then solution is

🟥 (a) acidic

🟦 (b) basic

🟩 (c) amphoteric

🟨 (d) neutral

✔ Correct Answer: 🟦 (b)
Short Reason: pH greater than 7 indicates alkaline (basic) nature.

8. Salt among the following is

🟥 (a) HCl

🟦 (b) KCl

🟩 (c) HNO₃

🟨 (d) H₂SO₄

✔ Correct Answer: 🟦 (b)
Short Reason: KCl is a salt formed from acid and base neutralization.

9. Substance that reacts with both acids and bases are called

🟥 (a) Amphoteric substances

🟦 (b) Conjugate acids

🟩 (c) Conjugate bases

🟨 (d) Buffers

✔ Correct Answer: 🟨 (a)
Short Reason: Amphoteric substances can act as both acid and base.

10. The reaction of acid and base to form salt and water is called

🟥 (a) Hydration

🟦 (b) Neutralization

🟩 (c) Hydrolysis

🟨 (d) both a and c

✔ Correct Answer: 🟦 (b)
Short Reason: Acid and base react to form salt and water in neutralization reaction.

11. Which of the following is a strong acid?

🟥 (a) CH₃COOH

🟦 (b) HCl

🟩 (c) NH₄OH

🟨 (d) H₂O

✔ Correct Answer: 🟦 (b)
Short Reason: HCl completely ionizes in water, so it is a strong acid.

12. Which of the following is a base?

🟥 (a) NaCl

🟦 (b) NaOH

🟩 (c) HCl

🟨 (d) H₂SO₄

✔ Correct Answer: 🟦 (b)
Short Reason: NaOH releases OH⁻ ions in water, so it is a base.

13. Which of the following is a neutral salt?

🟥 (a) NH₄Cl

🟦 (b) NaCl

🟩 (c) CH₃COONa

🟨 (d) NH₄OH

✔ Correct Answer: 🟦 (b)
Short Reason: NaCl is formed from strong acid and strong base, so it is neutral.

14. A solution with pH = 2 is:

🟥 (a) basic

🟦 (b) acidic

🟩 (c) neutral

🟨 (d) amphoteric

✔ Correct Answer: 🟦 (b)
Short Reason: pH less than 7 indicates acidic solution.

15. Which gas is released when acid reacts with metal?

🟥 (a) Oxygen

🟦 (b) Hydrogen

🟩 (c) Carbon dioxide

🟨 (d) Nitrogen

✔ Correct Answer: 🟦 (b)
Short Reason: Acid reacts with metal to produce hydrogen gas.

16. Which of the following is a weak acid?

🟥 (a) HCl

🟦 (b) HNO₃

🟩 (c) CH₃COOH

🟨 (d) H₂SO₄

✔ Correct Answer: 🟩 (c)
Short Reason: Acetic acid partially ionizes in water, so it is a weak acid.

17. Which indicator turns red in acidic solution?

🟥 (a) Phenolphthalein

🟦 (b) Litmus

🟩 (c) Methyl orange

🟨 (d) All of these

✔ Correct Answer: 🟩 (c)
Short Reason: Methyl orange turns red in acidic medium.

18. Which of the following is a basic salt?

🟥 (a) NaCl

🟦 (b) Na₂CO₃

🟩 (c) KNO₃

🟨 (d) HCl

✔ Correct Answer: 🟦 (b)
Short Reason: Na₂CO₃ is formed from strong base and weak acid, so it is basic.

19. Which of the following increases pH of a solution?

🟥 (a) Adding acid

🟦 (b) Adding base

🟩 (c) Adding salt

🟨 (d) Adding water only

✔ Correct Answer: 🟦 (b)
Short Reason: Bases increase hydroxide ions, raising pH.

20. Which of the following is used to test acids and bases?

🟥 (a) Oxygen gas

🟦 (b) Litmus paper

🟩 (c) Salt

🟨 (d) Sugar solution

✔ Correct Answer: 🟦 (b)
Short Reason: Litmus paper changes color in acids and bases.

21. pH is defined as:

🟥 (a) negative log of OH⁻

🟦 (b) negative log of H⁺

🟩 (c) positive log of H⁺

🟨 (d) positive log of OH⁻

✔ Correct Answer: 🟦 (b)
Short Reason: pH = -log[H⁺].

22. pOH of a solution is defined as:

🟥 (a) -log[H⁺]

🟦 (b) -log[OH⁻]

🟩 (c) log[OH⁻]

🟨 (d) log[H⁺]

✔ Correct Answer: 🟦 (b)
Short Reason: pOH = -log[OH⁻].

23. The sum of pH and pOH at 25°C is:

🟥 (a) 14

🟦 (b) 7

🟩 (c) 1

🟨 (d) 10

✔ Correct Answer: 🟥 (a)
Short Reason: pH + pOH = 14 at 25°C.

24. Kw represents:

🟥 (a) equilibrium constant of water

🟦 (b) ionic product of water

🟩 (c) acidity of water

🟨 (d) basicity of water

✔ Correct Answer: 🟦 (b)
Short Reason: Kw is the ionic product of water = [H⁺][OH⁻].

25. At 25°C, the value of Kw is:

🟥 (a) 1 × 10⁻⁷

🟦 (b) 1 × 10⁻¹⁴

🟩 (c) 1 × 10⁻¹⁰

🟨 (d) 1 × 10⁻⁵

✔ Correct Answer: 🟦 (b)
Short Reason: Kw of water at 25°C is 1 × 10⁻¹⁴.

26. If [H⁺] = 1 × 10⁻³ M, the pH of solution is:

🟥 (a) 1

🟦 (b) 3

🟩 (c) 11

🟨 (d) 7

✔ Correct Answer: 🟦 (b)
Short Reason: pH = -log(10⁻³) = 3.

27. If pH = 9, then pOH will be:

🟥 (a) 3

🟦 (b) 5

🟩 (c) 7

🟨 (d) 14

✔ Correct Answer: 🟥 (a)
Short Reason: pOH = 14 − pH = 14 − 9 = 5.

28. A solution has pOH = 2. Its pH is:

🟥 (a) 12

🟦 (b) 10

🟩 (c) 7

🟨 (d) 2

✔ Correct Answer: 🟥 (a)
Short Reason: pH = 14 − pOH = 12.

29. If [OH⁻] = 1 × 10⁻⁵ M, the pOH is:

🟥 (a) 5

🟦 (b) 9

🟩 (c) 7

🟨 (d) 3

✔ Correct Answer: 🟥 (a)
Short Reason: pOH = -log(10⁻⁵) = 5.

30. In pure water at 25°C, [H⁺] is:

🟥 (a) 1 × 10⁻⁷ M

🟦 (b) 1 × 10⁻¹⁴ M

🟩 (c) 1 × 10⁻⁵ M

🟨 (d) 7 × 10⁻¹ M

✔ Correct Answer: 🟥 (a)
Short Reason: Neutral water has [H⁺] = 10⁻⁷ M at 25°C.

📘 Smart Answers Short Questions of Model Test Questions Class 10 Chemistry Test # 3 for Chapter # 2 (Acids, bases and salts)

Prepared by Inam Jazbi – Learn Chemistry

Q1. What is Bronsted-Lowery acid-base theory? Define Bronsted-Lowry base and explain with an example that water is a Bronsted-Lowry base.

Answer

📌 Brønsted–Lowry Theory:
It states that an acid is a proton (H⁺) donor and a base is a proton (H⁺) acceptor.

📌 Definition of Brønsted-Lowry Base:
A substance that accepts a proton (H⁺) is called a Brønsted-Lowry base.

📌 Example (Water acting as base):
HCl + H₂O ⇌ H₃O⁺ + Cl⁻

🧪 Explanation:
In this reaction, water (H₂O) accepts a proton (H⁺) from hydrochloric acid (HCl) and forms hydronium ion (H₃O⁺). Therefore, water acts as a Brønsted–Lowry base.(H₃O⁺ is called conjugate acid and Cl⁻ is a conjugate base).

Q2. What are conjugate acid-base pairs? Explain with examples. Differentiate between proton transfer and electron pair transfer in acid-base reactions.

Answer

🔗 Conjugate Acid–Base Pair

A conjugate acid–base pair consists of two species that differ by the presence or absence of a proton (H⁺). When an acid loses a proton, its conjugate base is formed, and when a base gains a proton, its conjugate acid is formed.

📌 General Idea:
Acid → loses H⁺ → Conjugate Base
Base → gains H⁺ → Conjugate Acid

📌 Example:
CH₃COOH + H₂O ⇌ CH₃COO⁻ + H₃O⁺

⚗️ Proton Transfer (Brønsted–Lowry)

Acid donates H⁺ and base accepts H⁺.
Example: HCl + H₂O → H₃O⁺ + Cl⁻

⚡ Electron Pair Transfer (Lewis)

Base donates an electron pair and acid accepts it to form a coordinate bond.
Example: NH₃ + BF₃ → NH₃→BF₃

🧪 Key Difference:
• Brønsted–Lowry theory → transfer of H⁺ • Lewis theory → transfer of electron pair