NITROGEN AND ITS COMPOUNDS

Industrial Manufacture of Nitric(V) Acid

By the end of the lesson, the learner should be able to:
Describe catalytic oxidation process
Explain raw materials and conditions
Draw flow diagram of industrial process
Calculate theoretical yields and efficiency

Teacher exposition: Ostwald process - NH₃ oxidation with Pt-Rh catalyst at 900°C. Flow diagram: Oxidation chamber, cooling, absorption tower. Equations: NH₃ → NO → NO₂ → HNO₃. Economic factors: Catalyst cost, heat recovery.

Industrial process flow charts, Catalyst samples, Process condition charts, Efficiency calculation sheets

KLB Secondary Chemistry Form 3, Pages 145-147

NITROGEN AND ITS COMPOUNDS

Reactions of Dilute Nitric(V) Acid with Metals
Reactions of Dilute Nitric(V) Acid with Carbonates and Hydroxides

By the end of the lesson, the learner should be able to:
Test reactions with various metals
Explain absence of hydrogen gas production
Observe formation of nitrogen oxides
Write equations for metal-acid reactions
Test reactions with carbonates and hydrogen carbonates
Test neutralization with metal hydroxides and oxides
Identify products formed
Write balanced chemical equations

Experiment: Add dilute HNO₃ to Mg, Zn, Cu. Test gases produced with burning splint. Observe that no H₂ is produced (except with Mg in very dilute acid). Explain oxidation of any H₂ formed to water. Record observations and write equations.
Experiments: (a) Add dilute HNO₃ to Na₂CO₃, CaCO₃, ZnCO₃, CuCO₃, NaHCO₃. Test gas evolved with lime water. (b) Neutralize NaOH, CaO, CuO, PbO with dilute HNO₃. Record color changes and write equations.

Various metals (Mg, Zn, Cu), Dilute nitric acid, Test tubes, Gas testing apparatus, Burning splints
Various carbonates and hydroxides, Dilute nitric acid, Lime water, Universal indicator, Test tubes

KLB Secondary Chemistry Form 3, Pages 147-150

NITROGEN AND ITS COMPOUNDS

Reactions of Concentrated Nitric(V) Acid - Oxidizing Properties

By the end of the lesson, the learner should be able to:
Demonstrate strong oxidizing properties
Test reactions with FeSO₄, sulfur, and copper
Observe formation of nitrogen dioxide
Explain electron transfer in oxidation

Experiments: (a) Add concentrated HNO₃ to acidified FeSO₄ - observe color change. (b) Add to sulfur - observe reaction. (c) Add to copper turnings - observe vigorous reaction and brown fumes. Explain oxidizing power and reduction to NO₂.

Concentrated nitric acid, Iron(II) sulfate, Sulfur powder, Copper turnings, Test tubes, Fume cupboard access

KLB Secondary Chemistry Form 3, Pages 150-151

NITROGEN AND ITS COMPOUNDS

Reactions of Concentrated Nitric(V) Acid - Oxidizing Properties

By the end of the lesson, the learner should be able to:
Demonstrate strong oxidizing properties
Test reactions with FeSO₄, sulfur, and copper
Observe formation of nitrogen dioxide
Explain electron transfer in oxidation

Experiments: (a) Add concentrated HNO₃ to acidified FeSO₄ - observe color change. (b) Add to sulfur - observe reaction. (c) Add to copper turnings - observe vigorous reaction and brown fumes. Explain oxidizing power and reduction to NO₂.

Concentrated nitric acid, Iron(II) sulfate, Sulfur powder, Copper turnings, Test tubes, Fume cupboard access

KLB Secondary Chemistry Form 3, Pages 150-151

NITROGEN AND ITS COMPOUNDS

Uses of Nitric(V) Acid and Introduction to Nitrates

By the end of the lesson, the learner should be able to:
List major industrial uses of nitric acid
Explain importance in fertilizer manufacture
Describe use in explosives and dyes
Introduce nitrate salts and their preparation

Discussion: Uses - fertilizer production (NH₄NO₃), explosives (TNT), dyes, drugs, metal purification, etching. Introduction to nitrates as salts of nitric acid. Methods of preparation: acid + base, acid + carbonate, acid + metal. Examples of common nitrates.

Industrial use charts, Nitrate salt samples, Preparation method diagrams, Safety data sheets

KLB Secondary Chemistry Form 3, Pages 151

NITROGEN AND ITS COMPOUNDS

Action of Heat on Nitrates - Decomposition Patterns
Test for Nitrates - Brown Ring Test

By the end of the lesson, the learner should be able to:
Test thermal decomposition of different nitrates
Classify decomposition patterns based on metal reactivity
Identify products formed on heating
Write equations for decomposition reactions
Perform brown ring test for nitrates
Explain mechanism of complex formation
Use alternative copper test method
Apply tests to unknown samples

Experiment: Heat KNO₃, NaNO₃, Zn(NO₃)₂, Cu(NO₃)₂, NH₄NO₃ separately. Test gases with glowing splint. Observe residues. Classification: Group I nitrates → nitrite + O₂; Group II → oxide + NO₂ + O₂; NH₄NO₃ → N₂O + H₂O.
Experiments: (a) Brown ring test - add FeSO₄ solution to nitrate, then carefully add concentrated H₂SO₄. Observe brown ring formation. (b) Alternative test - warm nitrate with H₂SO₄ and copper turnings. Observe brown fumes. Test unknown samples.

Various nitrate salts, Test tubes, Bunsen burner, Gas collection apparatus, Glowing splints, Observation recording sheets
Sodium nitrate, Fresh FeSO₄ solution, Concentrated H₂SO₄, Copper turnings, Test tubes, Unknown nitrate samples

KLB Secondary Chemistry Form 3, Pages 151-153
KLB Secondary Chemistry Form 3, Pages 153-154

NITROGEN AND ITS COMPOUNDS

Environmental Pollution by Nitrogen Compounds

By the end of the lesson, the learner should be able to:
Explain sources of nitrogen pollution
Describe formation of acid rain
Discuss effects on environment and health
Evaluate pollution control measures

Teacher exposition: NOₓ from vehicles, HNO₃ formation in atmosphere, acid rain effects. Discussion: Chlorosis in plants, building corrosion, soil leaching, smog formation, health effects. Control measures: Catalytic converters, emission controls, proper fertilizer use.

Environmental pollution charts, Acid rain effect photos, Vehicle emission diagrams, Control measure illustrations

KLB Secondary Chemistry Form 3, Pages 154-157

NITROGEN AND ITS COMPOUNDS

Pollution Control and Environmental Solutions

By the end of the lesson, the learner should be able to:
Analyze methods to reduce nitrogen pollution
Design pollution control strategies
Evaluate effectiveness of current measures
Propose new solutions for environmental protection

Discussion and analysis: Catalytic converters in vehicles, sewage treatment, lime addition to soils/lakes, proper fertilizer application, industrial gas recycling. Group activity: Design pollution control strategy for local area. Evaluation of current measures.

Case studies, Pollution control technology information, Group activity worksheets, Local environmental data

KLB Secondary Chemistry Form 3, Pages 154-157

NITROGEN AND ITS COMPOUNDS

Pollution Control and Environmental Solutions

By the end of the lesson, the learner should be able to:
Analyze methods to reduce nitrogen pollution
Design pollution control strategies
Evaluate effectiveness of current measures
Propose new solutions for environmental protection

Discussion and analysis: Catalytic converters in vehicles, sewage treatment, lime addition to soils/lakes, proper fertilizer application, industrial gas recycling. Group activity: Design pollution control strategy for local area. Evaluation of current measures.

Case studies, Pollution control technology information, Group activity worksheets, Local environmental data

KLB Secondary Chemistry Form 3, Pages 154-157

NITROGEN AND ITS COMPOUNDS

Comprehensive Problem Solving - Nitrogen Chemistry
Laboratory Practical Assessment - Nitrogen Compounds

By the end of the lesson, the learner should be able to:
Solve complex problems involving nitrogen compounds
Apply knowledge to industrial processes
Calculate yields and percentages in reactions
Analyze experimental data and results
Demonstrate practical skills in nitrogen chemistry
Perform qualitative analysis of nitrogen compounds
Apply safety procedures correctly
Interpret experimental observations accurately

Problem-solving session: Mixed calculations involving nitrogen preparation, ammonia synthesis, nitric acid concentration, fertilizer analysis. Industrial application problems. Data analysis from experiments. Integration of all nitrogen chemistry concepts.
Practical examination: Identify unknown nitrogen compounds using chemical tests. Prepare specified nitrogen compounds. Demonstrate proper laboratory techniques. Safety assessment. Written report on observations and conclusions.

Scientific calculators, Comprehensive problem sets, Industrial data sheets, Experimental result tables
Unknown nitrogen compounds, All laboratory chemicals and apparatus used in chapter, Safety equipment, Assessment rubrics

KLB Secondary Chemistry Form 3, Pages 119-157

NITROGEN AND ITS COMPOUNDS

Industrial Applications and Economic Importance

By the end of the lesson, the learner should be able to:
Evaluate economic importance of nitrogen industry
Analyze industrial production costs and benefits
Compare different manufacturing processes
Assess impact on agricultural productivity

Case study analysis: Haber process economics, fertilizer industry impact, nitric acid production costs. Agricultural benefits: Crop yield improvements, food security. Economic calculations: Production costs, profit margins, environmental costs. Global nitrogen cycle importance.

Economic data sheets, Industry case studies, Agricultural statistics, Cost-benefit analysis templates

KLB Secondary Chemistry Form 3, Pages 119-157

NITROGEN AND ITS COMPOUNDS

Chapter Review and Integration

By the end of the lesson, the learner should be able to:
Synthesize all nitrogen chemistry concepts
Compare preparation methods for nitrogen compounds
Relate structure to properties and reactivity
Connect laboratory and industrial processes

Comprehensive review: Concept mapping of all nitrogen compounds and their relationships. Comparison tables: Preparation methods, properties, uses. Flow chart: Nitrogen cycle in industry and environment. Integration exercises connecting all topics.

Concept mapping materials, Comparison charts, Flow diagram templates, Integration worksheets

KLB Secondary Chemistry Form 3, Pages 119-157

SULPHUR AND ITS COMPOUNDS

Extraction of Sulphur
Allotropes of Sulphur

By the end of the lesson, the learner should be able to:
Define sulphur and state its position in the periodic table. Describe the occurrence of sulphur in nature. Explain the Frasch process for extraction of sulphur. Evaluate the effectiveness of the Frasch process.

Q/A: Review group VI elements and electron configuration of sulphur. Teacher demonstration: Using diagrams to explain the Frasch process setup. Discussion: Why ordinary mining is impossible for sulphur deposits. Group work: Students draw and label the Frasch process diagram.

Charts showing periodic table, Diagram of Frasch process, Samples of sulphur compounds (pyrites, gypsum)
Powdered sulphur, Carbon(IV) sulphide, Evaporating dish, Glass rod, Hand lens, Boiling tubes, Filter paper, Beakers

KLB Secondary Chemistry Form 4, Pages 160-161

SULPHUR AND ITS COMPOUNDS

Physical Properties of Sulphur - Solubility
Physical Properties of Sulphur - Effect of Heat
Chemical Properties of Sulphur - Reactions with Elements

By the end of the lesson, the learner should be able to:
Investigate the solubility of sulphur in different solvents. Explain the molecular structure of sulphur. Compare solubility in polar and non-polar solvents. State the physical properties of sulphur.
Investigate the effect of heat on sulphur. Describe changes in color and viscosity of molten sulphur. Explain the molecular changes occurring during heating. Identify "flowers of sulphur".

Practical work: Experiment 2(a) - Testing solubility of sulphur in water, benzene, methylbenzene, and carbon(IV) sulphide. Observation and recording in Table Discussion: Explain why sulphur dissolves in organic solvents but not water. Drawing: Puckered ring structure of S8 molecule.
Practical work: Experiment 2(b) - Heating sulphur and observing changes. Observation: Color changes from yellow to amber to reddish-brown to black. Testing viscosity by inverting test tube. Demonstration: Sublimation of sulphur vapour. Discussion: Breaking of S8 rings to form long chains.

Powdered sulphur, Water, Benzene, Methylbenzene, Carbon(IV) sulphide, Test tubes, Charts showing molecular structure
Powdered sulphur, Test tubes, Bunsen burner, Cold surface for condensation, Thermometer, Safety equipment
Sulphur, Iron powder, Copper powder, Oxygen gas jar, Deflagrating spoon, Moist litmus papers, Test tubes, Bunsen burner

KLB Secondary Chemistry Form 4, Pages 163-164
KLB Secondary Chemistry Form 4, Pages 164-165

SULPHUR AND ITS COMPOUNDS

Chemical Properties of Sulphur - Reactions with Acids
Uses of Sulphur and Introduction to Oxides

By the end of the lesson, the learner should be able to:
Investigate the reaction of sulphur with concentrated acids. Identify the products formed in these reactions. Write balanced equations for oxidation reactions. Test for sulphate ions using barium chloride.

Practical work: Experiment 3(b) - Reactions with concentrated nitric(V) acid, sulphuric(VI) acid, and hydrochloric acid. Testing with barium chloride solution. Observation: Formation of sulphate ions, brown fumes, no reaction with HCl. Discussion: Sulphur as a reducing agent, acids as oxidizing agents.

Sulphur powder, Concentrated HNO3, Concentrated H2SO4, Concentrated HCl, Barium chloride solution, Test tubes, Fume cupboard access
Charts showing uses of sulphur, Samples of vulcanized rubber, Fungicides, Industrial photographs, Textbook diagrams

KLB Secondary Chemistry Form 4, Pages 167-168

SULPHUR AND ITS COMPOUNDS

Preparation of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Describe laboratory preparation of sulphur(IV) oxide. Set up apparatus for gas preparation and collection. Write balanced equations for the preparation reactions. Explain the drying and collection methods used.

Practical work: Experiment 4 - Preparation of SO2 using sodium sulphite and dilute HCl. Apparatus setup: Round-bottomed flask, delivery tube, gas jars. Collection: Downward delivery method. Testing: Using acidified potassium chromate(VI) paper. Alternative method: Copper + concentrated H2SO

Sodium sulphite, Dilute HCl, Round-bottomed flask, Delivery tubes, Gas jars, Concentrated H2SO4 for drying, Acidified potassium chromate(VI) paper

KLB Secondary Chemistry Form 4, Pages 170-171

SULPHUR AND ITS COMPOUNDS

Physical and Chemical Properties of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Investigate the physical properties of SO2 gas. Test the solubility and acidity of SO Write equations for formation of sulphurous acid. Identify the acidic nature of SO

Practical work: Experiment 5 - Testing color, smell, solubility in water. Testing with dry and moist litmus papers. Universal indicator tests with water and NaOH. Formation of normal and acid salts. Recording observations in Table Safety: Proper ventilation due to toxic nature.

SO2 gas from previous preparation, Litmus papers, Universal indicator, 0.1M NaOH solution, Water, Test tubes, Safety equipment

KLB Secondary Chemistry Form 4, Pages 171-173

SULPHUR AND ITS COMPOUNDS

Bleaching Action of Sulphur(IV) Oxide
Reducing Action of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Investigate the bleaching properties of SO Compare SO2 bleaching with chlorine bleaching. Explain the mechanism of SO2 bleaching. Relate bleaching to paper manufacturing.
Investigate SO2 as a reducing agent. Test reactions with various oxidizing agents. Write ionic equations for redox reactions. Identify color changes in redox reactions.

Practical work: Experiment 6 - Placing colored flower petals in SO2 gas. Observation: Temporary bleaching effect. Discussion: SO2 + H2O → H2SO3, reduction of organic dyes. Comparison: Permanent vs temporary bleaching. Application: Paper industry bleaching processes.
Practical work: Experiment 7 - Testing SO2 with acidified potassium dichromate(VI), potassium manganate(VII), bromine water, iron(III) chloride. Recording observations in Table 6. Color changes: Orange to green, purple to colorless, brown to colorless, yellow to pale green. Writing half-equations and overall equations.

Colored flower petals (red/blue), SO2 gas jars, Hand lens for observation, Charts comparing bleaching agents
SO2 gas, Acidified K2Cr2O7, Acidified KMnO4, Bromine water, Iron(III) chloride solution, Concentrated HNO3, Test tubes

KLB Secondary Chemistry Form 4, Pages 173
KLB Secondary Chemistry Form 4, Pages 173-176

SULPHUR AND ITS COMPOUNDS

Oxidising Action of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Investigate SO2 as an oxidizing agent. Demonstrate reaction with stronger reducing agents. Explain the dual nature of SO Write equations for oxidation reactions by SO

Practical work: Experiment 8 - Lowering burning magnesium into SO2 gas. Observation: Continued burning, white fumes of MgO, yellow specks of sulphur. Reaction with hydrogen sulphide gas (demonstration). Discussion: SO2 decomposition providing oxygen. Writing equations: 2Mg + SO2 → 2MgO + S.

SO2 gas jars, Magnesium ribbon, Deflagrating spoon, Hydrogen sulphide gas, Water droppers, Safety equipment

KLB Secondary Chemistry Form 4, Pages 176-177

SULPHUR AND ITS COMPOUNDS

Test for Sulphate and Sulphite Ions & Uses of SO2

By the end of the lesson, the learner should be able to:
Carry out confirmatory tests for sulphate and sulphite ions. Distinguish between sulphate and sulphite using chemical tests. List the uses of sulphur(IV) oxide. Explain the applications in industry.

Practical work: Experiment 9 - Testing sodium sulphate and sodium sulphite with barium chloride. Adding dilute HCl to precipitates. Recording observations in Table 8. Discussion: BaSO4 insoluble in acid, BaSO3 dissolves. Uses: Raw material for H2SO4, bleaching wood pulp, fumigant, preservative.

Sodium sulphate solution, Sodium sulphite solution, Barium chloride solution, Dilute HCl, Test tubes, Charts showing industrial uses

KLB Secondary Chemistry Form 4, Pages 178-179

SULPHUR AND ITS COMPOUNDS

Large-scale Manufacture of Sulphuric(VI) Acid - Contact Process

By the end of the lesson, the learner should be able to:
Describe the contact process for manufacturing H2SO Identify raw materials and conditions used. Explain the role of catalyst in the process. Draw flow diagrams of the contact process.

Study of flow diagram: Figure 12 - Contact process. Discussion: Raw materials (sulphur, air), burning sulphur to SO Purification: Electrostatic precipitation, drying with H2SO Catalytic chamber: V2O5 catalyst at 450°C, 2-3 atmospheres. Formation of oleum: H2S2O7. Safety and environmental considerations.

Flow chart diagrams, Charts showing industrial plant, Samples of catalyst (V2O5), Photographs of Thika chemical plant, Calculator for percentage calculations

KLB Secondary Chemistry Form 4, Pages 179-181

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Dehydrating Properties

By the end of the lesson, the learner should be able to:
Investigate the dehydrating properties of concentrated H2SO Demonstrate removal of water from hydrated salts. Show dehydration of organic compounds. Explain the hygroscopic nature of the acid.

Practical work: Experiment 10 - Adding concentrated H2SO4 to copper(II) sulphate crystals, sucrose crystals, ethanol. Observations: Blue to white crystals, charring of sugar, formation of ethene. Safety: Proper dilution technique - acid to water. Testing evolved gases. Discussion: Chemical vs physical dehydration.

Concentrated H2SO4, Copper(II) sulphate crystals, Sucrose, Ethanol, KMnO4 solution, Test tubes, Beakers, Safety equipment, Fume cupboard

KLB Secondary Chemistry Form 4, Pages 181-183

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Oxidizing Properties

By the end of the lesson, the learner should be able to:
Investigate the oxidizing properties of concentrated H2SO Test reactions with metals and non-metals. Identify the products of oxidation reactions. Write balanced equations for redox reactions.

Practical work: Experiment 10 (continued) - Reactions with copper foil, zinc granules, charcoal. Testing evolved gases with acidified K2Cr2O7 paper, lime water. Observations: SO2 evolution, color changes. Discussion: H2SO4 → SO2 + H2O + [O]. Writing half-equations and overall equations.

Copper foil, Zinc granules, Charcoal powder, Concentrated H2SO4, Acidified K2Cr2O7 paper, Lime water, Test tubes, Bunsen burner

KLB Secondary Chemistry Form 4, Pages 183-184

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Displacement Reactions

By the end of the lesson, the learner should be able to:
Investigate acid displacement reactions. Demonstrate formation of volatile acids. Test the evolved gases for identification. Write equations for displacement reactions.

Practical work: Experiment 10 (continued) - Reactions with potassium nitrate and sodium chloride. Testing evolved gases with moist blue litmus, concentrated ammonia. Observations: Brown fumes (NO2), white fumes (HCl). Discussion: Less volatile acid displacing more volatile acids. Industrial applications.

Potassium nitrate crystals, Sodium chloride crystals, Concentrated H2SO4, Moist blue litmus paper, Concentrated ammonia, Test tubes, Bunsen burner

KLB Secondary Chemistry Form 4, Pages 184

SULPHUR AND ITS COMPOUNDS

Reactions of Dilute Sulphuric(VI) Acid - With Metals

By the end of the lesson, the learner should be able to:
Investigate reactions of dilute H2SO4 with metals. Compare reactivity of different metals. Test for hydrogen gas evolution. Relate reactions to reactivity series.

Practical work: Experiment 11 - Reactions with magnesium, zinc, copper. Testing evolved gas with burning splint. Recording observations in Table 10. Discussion: More reactive metals above hydrogen displace it. Vigour of reaction decreases down reactivity series. Writing ionic equations.

Magnesium ribbon, Zinc granules, Copper turnings, Dilute H2SO4, Test tubes, Burning splints, Reactivity series chart

KLB Secondary Chemistry Form 4, Pages 184-185

SULPHUR AND ITS COMPOUNDS

Reactions of Dilute Sulphuric(VI) Acid - With Carbonates
Reactions of Dilute Sulphuric(VI) Acid - With Oxides and Hydroxides

By the end of the lesson, the learner should be able to:
Investigate reactions of dilute H2SO4 with carbonates. Test for carbon dioxide evolution. Explain why some reactions stop prematurely. Compare reactions of different metal carbonates.
Investigate reactions of dilute H2SO4 with metal oxides and hydroxides. Identify neutralization reactions. Explain formation of insoluble sulphates. Write equations for acid-base reactions.

Practical work: Experiment 12 - Reactions with sodium carbonate, zinc carbonate, calcium carbonate, copper(II) carbonate. Testing evolved gas with lime water. Recording observations in Table 1 Discussion: Formation of insoluble calcium sulphate coating. Effervescence and CO2 identification.
Practical work: Experiment 13 - Reactions with magnesium oxide, zinc oxide, copper(II) oxide, lead(II) oxide, sodium hydroxide. Recording observations in Table 1 Discussion: Salt and water formation, immediate stopping with lead(II) oxide due to insoluble PbSO Acid-base neutralization concept.

Sodium carbonate, Zinc carbonate, Calcium carbonate, Copper(II) carbonate, Dilute H2SO4, Lime water, Test tubes
Metal oxides (MgO, ZnO, CuO, PbO), NaOH solution, 2M H2SO4, Test tubes, Bunsen burner for warming

KLB Secondary Chemistry Form 4, Pages 185-186
KLB Secondary Chemistry Form 4, Pages 186-187

SULPHUR AND ITS COMPOUNDS

Hydrogen Sulphide - Preparation and Physical Properties

By the end of the lesson, the learner should be able to:
Describe laboratory preparation of hydrogen sulphide. Set up apparatus for H2S preparation. State the physical properties of H2S. Explain the toxicity and safety precautions.

Demonstration: Figure 13 apparatus setup for H2S preparation. Reaction: FeS + 2HCl → FeCl2 + H2S. Collection over warm water due to solubility. Drying: Using anhydrous CaCl2 (not H2SO4). Properties: Colorless, rotten egg smell, poisonous, denser than air. Safety precautions in handling.

Iron(II) sulphide, Dilute HCl, Apparatus for gas generation, Anhydrous CaCl2, Gas jars, Safety equipment, Fume cupboard

KLB Secondary Chemistry Form 4, Pages 187-188

SULPHUR AND ITS COMPOUNDS

Hydrogen Sulphide - Preparation and Physical Properties

By the end of the lesson, the learner should be able to:
Describe laboratory preparation of hydrogen sulphide. Set up apparatus for H2S preparation. State the physical properties of H2S. Explain the toxicity and safety precautions.

Demonstration: Figure 13 apparatus setup for H2S preparation. Reaction: FeS + 2HCl → FeCl2 + H2S. Collection over warm water due to solubility. Drying: Using anhydrous CaCl2 (not H2SO4). Properties: Colorless, rotten egg smell, poisonous, denser than air. Safety precautions in handling.

Iron(II) sulphide, Dilute HCl, Apparatus for gas generation, Anhydrous CaCl2, Gas jars, Safety equipment, Fume cupboard

KLB Secondary Chemistry Form 4, Pages 187-188

SULPHUR AND ITS COMPOUNDS

Chemical Properties of Hydrogen Sulphide

By the end of the lesson, the learner should be able to:
Investigate H2S as a reducing agent. Test reactions with oxidizing agents. Demonstrate precipitation of metal sulphides. Write ionic equations for redox reactions.

Practical demonstrations: H2S with bromine water, iron(III) chloride, acidified KMnO4, K2Cr2O7. Precipitation tests: H2S with copper(II) sulphate, lead(II) nitrate, zinc sulphate. Color changes: Brown to colorless, yellow to green, purple to colorless. Formation of black, yellow, and white precipitates.

H2S gas, Bromine water, Iron(III) chloride, KMnO4, K2Cr2O7, Metal salt solutions, Test tubes, Droppers

KLB Secondary Chemistry Form 4, Pages 188-190

SULPHUR AND ITS COMPOUNDS

Pollution Effects and Summary

By the end of the lesson, the learner should be able to:
Explain environmental pollution by sulphur compounds. Describe formation and effects of acid rain. Suggest methods to reduce sulphur pollution. Summarize key concepts of sulphur chemistry.

Discussion: Sources of SO2 pollution - burning fossil fuels, metal extraction, H2SO4 manufacture. Formation of acid rain: SO2 + H2O → H2SO3 → H2SO Effects: Plant damage, aquatic life destruction, building corrosion, soil acidification. Control measures: Scrubbing with Ca(OH)2, catalytic converters. Revision: Key reactions, properties, uses.

Charts showing pollution effects, Photographs of acid rain damage, Environmental data, Summary charts of reactions, Industrial pollution control diagrams

KLB Secondary Chemistry Form 4, Pages 190-194