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Are you a Class 10 ICSE student preparing for your Chemistry board exams? Ammonia is one of the most important chapters in the ICSE Class 10 Chemistry syllabus. At Dhingra Classes, Nashik, we have designed this comprehensive guide to help you master every concept with 50 solved MCQs, 15 solved short answer questions, and 15 solved long answer questions.

This article covers preparation of ammonia gas, physical and chemical properties, tests for ammonia, uses, and numerical problems — all explained step-by-step for easy understanding.

📚 Introduction to Ammonia

Ammonia (NH₃) is a colourless, pungent-smelling gas that is highly soluble in water. It is a weak base and is widely used in fertilizers, cleaning agents, and refrigeration.

🔑 Key Facts:

• Molecular Formula: NH₃

• Molecular Mass: 17 g/mol

• Nature: Basic gas

• Solubility: Highly soluble in water (forms ammonium hydroxide)

• Nature of Solution: Weak base

• Odour: Pungent, irritating

🧪 Preparation of Ammonia Gas

Laboratory Preparation:

Method: Heating ammonium chloride with slaked lime (calcium hydroxide).

Equation:
2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2H₂O + 2NH₃↑

Apparatus:

• Round-bottom flask

• Delivery tube

• Gas jar

• Drying tower

Collection: By downward displacement of air (since ammonia is lighter than air).

Drying Agent: Quicklime (CaO) — not conc. H₂SO₄ or P₂O₅ as they react with ammonia.

Industrial Preparation:

Method: Haber’s Process — Direct combination of nitrogen and hydrogen.

Equation:
N₂ + 3H₂ ⇌ 2NH₃ (at 450°C, 200 atm, iron catalyst)

🧪 Physical Properties of Ammonia

🧪 Chemical Properties of Ammonia

1. Basic Nature:

Ammonia is basic in nature. It turns red litmus blue.

2. Reaction with Acids:

NH₃ + HCl → NH₄Cl (White fumes of ammonium chloride)

3. Reaction with Water:

NH₃ + H₂O → NH₄OH (Ammonium hydroxide)

4. Reaction with Metal Salts:

CuSO₄ + 2NH₄OH → Cu(OH)₂↓ + (NH₄)₂SO₄ (Blue precipitate)

5. Reaction with Oxygen:

4NH₃ + 5O₂ → 4NO + 6H₂O (Catalytic oxidation)

6. Reaction with Chlorine:

2NH₃ + 3Cl₂ → N₂ + 6HCl

🧪 Tests for Ammonia Gas

📝 SECTION 1: 50 SOLVED MCQs on Ammonia

Q1. The molecular formula of ammonia is:

(a) NH₄ (b) NH₃ (c) NO₂ (d) N₂O
Ans: (b) NH₃

Q2. Ammonia gas is:

(a) Basic (b) Acidic (c) Neutral (d) Amphoteric
Ans: (a) Basic

Q3. The molecular mass of ammonia is:

(a) 16 (b) 17 (c) 18 (d) 19
Ans: (b) 17

Q4. Ammonia gas is collected by:

(a) Downward displacement of air (b) Upward displacement of air (c) Downward displacement of water (d) Upward displacement of water
Ans: (a) Downward displacement of air

Q5. Which chemical is used in the laboratory preparation of ammonia?

(a) NH₄Cl + Ca(OH)₂ (b) NH₄Cl + NaOH (c) NH₄Cl + H₂SO₄ (d) NH₄Cl + HCl
Ans: (a) NH₄Cl + Ca(OH)₂

Q6. The gas evolved when NH₄Cl reacts with Ca(OH)₂ is:

(a) Cl₂ (b) NH₃ (c) SO₂ (d) H₂
Ans: (b) NH₃

Q7. Ammonia gas turns red litmus:

(a) Red (b) Blue (c) Green (d) Yellow
Ans: (b) Blue

Q8. The white fumes produced when NH₃ reacts with HCl is:

(a) NH₄Cl (b) NaCl (c) NH₄OH (d) Cl₂
Ans: (a) NH₄Cl

Q9. Ammonia is a:

(a) Weak base (b) Strong base (c) Weak acid (d) Strong acid
Ans: (a) Weak base

Q10. The pH of ammonia solution is:

(a) 7 (b) More than 7 (c) Less than 7 (d) 14
Ans: (b) More than 7

Q11. Ammonia gas is dried using:

(a) Conc. H₂SO₄ (b) P₂O₅ (c) Quicklime (d) CaCl₂
Ans: (c) Quicklime

Q12. The reaction of NH₃ with water produces:

(a) NH₄OH (b) NH₄Cl (c) NH₄NO₃ (d) NH₄SO₄
Ans: (a) NH₄OH

Q13. NH₃ reacts with CuSO₄ to produce:

(a) Blue precipitate (b) White precipitate (c) Yellow precipitate (d) Black precipitate
Ans: (a) Blue precipitate

Q14. The compound formed when NH₃ reacts with HCl is:

(a) NH₄Cl (b) NH₄OH (c) NH₄NO₃ (d) NH₄SO₄
Ans: (a) NH₄Cl

Q15. Ammonia gas is:

(a) Lighter than air (b) Heavier than air (c) Same as air (d) None of these
Ans: (a) Lighter than air

Q16. The nature of NH₃ gas is:

(a) Basic (b) Acidic (c) Neutral (d) Amphoteric
Ans: (a) Basic

Q17. Ammonia gas is highly soluble in:

(a) Oil (b) Water (c) Alcohol (d) Benzene
Ans: (b) Water

Q18. The reaction of NH₃ with O₂ produces:

(a) NO (b) NO₂ (c) N₂O (d) N₂O₅
Ans: (a) NO

Q19. The gas produced when NH₃ reacts with chlorine is:

(a) N₂ (b) H₂ (c) O₂ (d) Cl₂
Ans: (a) N₂

Q20. Ammonia is used in the manufacture of:

(a) Fertilizers (b) Glass (c) Cement (d) Steel
Ans: (a) Fertilizers

Q21. The compound formed when NH₃ reacts with H₂SO₄ is:

(a) (NH₄)₂SO₄ (b) NH₄HSO₄ (c) NH₄SO₄ (d) NH₄S
Ans: (a) (NH₄)₂SO₄

Q22. Ammonia gas is liquefied under:

(a) Low pressure (b) High pressure (c) Low temperature (d) Both (b) and (c)
Ans: (d) Both (b) and (c)

Q23. The test for NH₃ gas using Nessler’s reagent gives:

(a) Brown precipitate (b) White precipitate (c) Yellow precipitate (d) Black precipitate
Ans: (a) Brown precipitate

Q24. The brown precipitate formed in the test for NH₃ gas is:

(a) NH₂HgO (b) NH₄Cl (c) NH₄OH (d) NH₄NO₃
Ans: (a) NH₂HgO

Q25. Ammonia gas is:

(a) Colourless (b) Green (c) Yellow (d) Brown
Ans: (a) Colourless

Q26. The odour of NH₃ gas is:

(a) Pleasant (b) Pungent (c) Odourless (d) Sweet
Ans: (b) Pungent

Q27. Ammonia gas is:

(a) Non-corrosive (b) Corrosive (c) Neutral (d) Basic
Ans: (b) Corrosive

Q28. The reaction of NH₃ with HCl is a:

(a) Combination reaction (b) Decomposition reaction (c) Displacement reaction (d) Double displacement reaction
Ans: (a) Combination reaction

Q29. Ammonia is used in:

(a) Refrigeration (b) Glass (c) Cement (d) Steel
Ans: (a) Refrigeration

Q30. The catalyst used in Haber’s process is:

(a) Iron (b) Platinum (c) Nickel (d) Copper
Ans: (a) Iron

Q31. Ammonia is:

(a) Monobasic (b) Dibasic (c) Tribasic (d) Tetrabasic
Ans: (a) Monobasic

Q32. The reaction of NH₃ with metals produces:

(a) H₂ (b) O₂ (c) CO₂ (d) N₂
Ans: (a) H₂

Q33. Ammonia is:

(a) Reducing agent (b) Oxidising agent (c) Both (d) None
Ans: (a) Reducing agent

Q34. The gas produced when NH₃ reacts with Zn is:

(a) H₂ (b) O₂ (c) CO₂ (d) N₂
Ans: (a) H₂

Q35. Ammonia gas is:

(a) Soluble in water (b) Insoluble in water (c) Sparingly soluble (d) None
Ans: (a) Soluble in water

Q36. The reaction of NH₃ with CaCO₃ produces:

(a) CaCl₂ + H₂O + CO₂ (b) CaCl₂ + H₂ (c) CaCl₂ + O₂ (d) CaCl₂ + N₂
Ans: (a) CaCl₂ + H₂O + CO₂

Q37. Ammonia gas is used in the laboratory as:

(a) Oxidising agent (b) Reducing agent (c) Reagent (d) Catalyst
Ans: (c) Reagent

Q38. The reaction of NH₃ with Mg produces:

(a) MgCl₂ + H₂ (b) MgCl₂ + O₂ (c) MgCl₂ + CO₂ (d) MgCl₂ + N₂
Ans: (a) MgCl₂ + H₂

Q39. Ammonia gas is:

(a) Polar (b) Non-polar (c) Ionic (d) Metallic
Ans: (a) Polar

Q40. The reaction of NH₃ with Fe produces:

(a) FeCl₂ + H₂ (b) FeCl₃ + H₂ (c) FeCl₂ + O₂ (d) FeCl₃ + O₂
Ans: (a) FeCl₂ + H₂

Q41. Ammonia gas is:

(a) Basic (b) Acidic (c) Neutral (d) Amphoteric
Ans: (a) Basic

Q42. The reaction of NH₃ with NaHCO₃ produces:

(a) NaCl + H₂O + CO₂ (b) NaCl + H₂ (c) NaCl + O₂ (d) NaCl + N₂
Ans: (a) NaCl + H₂O + CO₂

Q43. Ammonia gas is:

(a) Toxic (b) Non-toxic (c) Harmless (d) None
Ans: (a) Toxic

Q44. The reaction of NH₃ with Al produces:

(a) AlCl₃ + H₂ (b) AlCl₃ + O₂ (c) AlCl₃ + CO₂ (d) AlCl₃ + N₂
Ans: (a) AlCl₃ + H₂

Q45. Ammonia gas is:

(a) Inflammable (b) Non-inflammable (c) Explosive (d) None
Ans: (b) Non-inflammable

Q46. The reaction of NH₃ with CaO produces:

(a) CaCl₂ + H₂O (b) CaCl₂ + H₂ (c) CaCl₂ + CO₂ (d) CaCl₂ + O₂
Ans: (a) CaCl₂ + H₂O

Q47. Ammonia gas is:

(a) Heavier than air (b) Lighter than air (c) Same as air (d) None
Ans: (b) Lighter than air

Q48. The reaction of NH₃ with Pb(NO₃)₂ produces:

(a) PbCl₂ + HNO₃ (b) PbCl₂ + H₂ (c) PbCl₂ + O₂ (d) PbCl₂ + N₂
Ans: (a) PbCl₂ + HNO₃

Q49. Ammonia gas is:

(a) Colourless (b) Coloured (c) Black (d) White
Ans: (a) Colourless

Q50. The reaction of NH₃ with AgNO₃ produces:

(a) AgCl + HNO₃ (b) AgCl + H₂ (c) AgCl + O₂ (d) AgCl + N₂
Ans: (a) AgCl + HNO₃

📝 SECTION 2: 15 SOLVED SHORT ANSWER QUESTIONS on Ammonia

Q1. How is ammonia gas prepared in the laboratory?

Ans:
Ammonia gas is prepared by heating ammonium chloride with slaked lime.
2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2H₂O + 2NH₃↑
The gas is collected by downward displacement of air.

Q2. Why is ammonia gas collected by downward displacement of air?

Ans:
Ammonia gas is collected by downward displacement of air because it is lighter than air and highly soluble in water.

Q3. What is the nature of ammonia gas? How is it tested?

Ans:
Ammonia gas is basic in nature. It turns red litmus blue. When a glass rod dipped in hydrochloric acid is brought near ammonia gas, white fumes of ammonium chloride are formed.

Q4. Write the reaction of ammonia with hydrochloric acid.

Ans:
NH₃ + HCl → NH₄Cl
White fumes of ammonium chloride are formed.

Q5. What happens when ammonia gas is dissolved in water?

Ans:
When ammonia gas is dissolved in water, it forms ammonium hydroxide, a weak base. The solution conducts electricity.

Q6. Write the reaction of ammonia with copper sulphate.

Ans:
CuSO₄ + 2NH₄OH → Cu(OH)₂↓ + (NH₄)₂SO₄
A blue precipitate of copper hydroxide is formed.

Q7. Write the reaction of ammonia with oxygen.

Ans:
4NH₃ + 5O₂ → 4NO + 6H₂O
Nitric oxide and water are formed.

Q8. What is the action of ammonia on red litmus paper?

Ans:
Ammonia turns red litmus paper blue, indicating its basic nature.

Q9. Why is ammonia gas not dried using conc. H₂SO₄?

Ans:
Ammonia gas is not dried using conc. H₂SO₄ because it is a base and reacts with H₂SO₄ to form ammonium sulphate.

Q10. What is the test for ammonia using Nessler’s reagent?

Ans:
When Nessler’s reagent is added to ammonia, a brown precipitate of ammonium mercury iodide is formed.

Q11. Write the reaction of ammonia with chlorine.

Ans:
2NH₃ + 3Cl₂ → N₂ + 6HCl
Nitrogen and hydrogen chloride are formed.

Q12. What is the action of ammonia on sodium hydroxide?

Ans:
NaOH + NH₃ → No reaction (both are bases)

Q13. Why is ammonia used in refrigeration?

Ans:
Ammonia is used in refrigeration because it is easily liquefied under pressure and absorbs heat during evaporation.

Q14. What is the industrial method for the preparation of ammonia?

Ans:
Industrially, ammonia is prepared by Haber’s Process:
N₂ + 3H₂ ⇌ 2NH₃ (at 450°C, 200 atm, iron catalyst)

Q15. Write two uses of ammonia.

Ans:

1. In the manufacture of fertilizers.

2. In refrigeration.

📝 SECTION 3: 15 SOLVED LONG ANSWER QUESTIONS on Ammonia

Q1. Describe the laboratory preparation of ammonia gas with a labelled diagram.

Ans:
Laboratory Preparation:

• Apparatus: Round-bottom flask, delivery tube, gas jar, drying tower.

• Chemicals: Ammonium chloride (NH₄Cl) and slaked lime (Ca(OH)₂).

• Method: NH₄Cl and Ca(OH)₂ are mixed and heated in the flask. NH₃ gas is evolved.

• Equation: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2H₂O + 2NH₃↑

• Collection: By downward displacement of air.

• Drying: By passing through quicklime (CaO).

Q2. Explain the physical properties of ammonia gas.

Ans:

• Colour: Colourless

• Odour: Pungent, irritating

• Taste: Alkaline

• Solubility: Highly soluble in water

• Density: Lighter than air

• Nature: Basic

• Liquefaction: Easily liquefied under pressure

• Freezing Point: -77.7°C

• Boiling Point: -33.3°C

Q3. Explain the chemical properties of ammonia gas.

Ans:

1. Basic nature: Turns red litmus blue.

2. With acids: NH₃ + HCl → NH₄Cl

3. With water: NH₃ + H₂O → NH₄OH

4. With metal salts: CuSO₄ + 2NH₄OH → Cu(OH)₂↓ + (NH₄)₂SO₄

5. With oxygen: 4NH₃ + 5O₂ → 4NO + 6H₂O

6. With chlorine: 2NH₃ + 3Cl₂ → N₂ + 6HCl

Q4. What is ammonia solution? Write its properties and uses.

Ans:
Ammonia solution is an aqueous solution of NH₃ gas.

Properties:

• Weak base

• Colourless, corrosive liquid

• Conducts electricity

• pH > 7

Uses:

1. Manufacture of fertilizers

2. Refrigeration

3. Cleaning agents

4. Production of nitric acid

5. Laboratory reagent

Q5. Describe the tests for ammonia gas.

Ans:

1. Litmus test: Turns red litmus blue.

2. HCl test: White fumes with HCl.

3. Nessler’s reagent: Brown precipitate.

4. Moist red litmus: Turns blue.

Q6. Write the reaction of NH₃ with:

(a) HCl (b) H₂O (c) CuSO₄ (d) O₂ (e) Cl₂
Ans:
(a) NH₃ + HCl → NH₄Cl
(b) NH₃ + H₂O → NH₄OH
(c) CuSO₄ + 2NH₄OH → Cu(OH)₂↓ + (NH₄)₂SO₄
(d) 4NH₃ + 5O₂ → 4NO + 6H₂O
(e) 2NH₃ + 3Cl₂ → N₂ + 6HCl

Q7. Explain the industrial preparation of ammonia.

Ans:
Industrially, ammonia is prepared by Haber’s Process:

• Reaction: N₂ + 3H₂ ⇌ 2NH₃

• Conditions: 450°C, 200 atm, iron catalyst

• Source of N₂: Air

• Source of H₂: Water gas

• Yield: About 15%

Q8. Why is ammonia gas not collected over water?

Ans:
Ammonia gas is highly soluble in water, so it cannot be collected over water. It is collected by downward displacement of air because it is lighter than air.

Q9. What is the role of ammonia in the human body?

Ans:

• Protein metabolism: Ammonia is produced during protein metabolism.

• Urea formation: It is converted to urea in the liver.

• Excretion: Urea is excreted by the kidneys.

Q10. Write the reaction of NH₃ with:

(a) CaCO₃ (b) Mg (c) Fe (d) Al
Ans:
(a) CaCO₃ + 2NH₃ → No reaction
(b) Mg + 2NH₃ → Mg(NH₂)₂ + H₂
(c) Fe + 2NH₃ → Fe(NH₂)₂ + H₂
(d) 2Al + 6NH₃ → 2Al(NH₂)₃ + 3H₂

Q11. Explain the drying of ammonia gas.

Ans:
Ammonia gas is dried by passing through quicklime (CaO). It cannot be dried using conc. H₂SO₄ or P₂O₅ because they react with ammonia.

Q12. What is the action of NH₃ on:

(a) Red litmus (b) Hydrochloric acid (c) Copper sulphate
Ans:
(a) Turns blue
(b) NH₃ + HCl → NH₄Cl (White fumes)
(c) CuSO₄ + 2NH₄OH → Cu(OH)₂↓ + (NH₄)₂SO₄ (Blue precipitate)

Q13. Write the difference between ammonia gas and ammonium hydroxide.

Ans:

Q14. Explain the preparation of ammonium hydroxide from ammonia gas.

Ans:
Ammonia gas is dissolved in water to form ammonium hydroxide. The process is highly exothermic. The gas is passed through water, and the resulting solution is ammonium hydroxide.

Q15. Write any five uses of ammonia.

Ans:

1. Manufacture of fertilizers

2. Refrigeration

3. Cleaning agents

4. Production of nitric acid

5. Laboratory reagent

6. Manufacture of dyes and plastics

🎯 Exam Tips for Class 10 ICSE Chemistry Students

🧪 Understand the preparation methods — laboratory and industrial

📝 Memorise all chemical equations — they are frequently asked

🔬 Practise diagram-based questions for full marks

📊 Learn the tests for ammonia gas — litmus, HCl, Nessler’s reagent

✅ Revise uses of ammonia in daily life and industry

🔗 Connect concepts to real-life applications like fertilizers and refrigeration

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