Curriculum
Chemistry
Chapter 1 - Transition Elements and Iron Metallurgy
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1.1Where they are in the periodic table1.2The main transition elements (d-block)1.3The four transition series1.4Economic importance of the first-series elements1.5Electron configurations of the first series1.6Rules for filling1.7Configurations of the common ions1.8Why Fe(II) is easily oxidized to Fe(III) but Mn(II) is not1.9Oxidation-state rules for the series1.10Calculating oxidation states in compounds1.11Definition of a transition element
Chapter 2 - Chemical Analysis
0/221.1Revision of concepts and laws needed in this chapter1.2Importance1.3Kinds of analysis1.4Qualitative analysis1.5A. Identification of acid radicals (anions)1.6(1) Dilute hydrochloric acid group1.7(2) Concentrated sulphuric acid group1.8(3) Barium chloride group1.9Practical differentiation between pairs of salts (typical exam type)1.10Reasoning questions1.11Detailed Comparison Matrix: Diagnostic Silver Nitrate (AgNO3) Confirmatory Matrix
Chapter 3 - Chemical Equilibrium
0/221.1The equilibrium system1.2Types of chemical reactions1.3Chemical equilibrium1.4Rate of reaction1.5Factors affecting the rate of a reaction1.6Nature of the reactants1.7Concentration and the law of mass action1.8Temperature — collision theory1.9Pressure1.10Le Chatelier's principle1.11Catalysts1.12Light
2.1Strong and weak electrolytes2.2Hydronium ion2.3Definitions2.4Ostwald's dilution law2.5Hydronium ion concentration of a weak acid2.6Hydroxide ion concentration of a weak base2.7Ionization of water and the ionic product Kw2.8pH and pOH2.9Solubility and solubility product2.10Summary of key relations
Chapter 4 - Electrochemistry
0/331.1The starting experiment: zinc in copper sulphate1.2The idea behind the galvanic cell1.3Construction of the Daniell cell1.4What happens at each electrode1.5When does the current stop?1.6The salt bridge — what it is and why it is needed1.7Why we need a reference1.8The standard hydrogen electrode1.9Standard electrode potentials1.10Measuring an electrode potential (idea of the experiment)1.11Definition1.12What the series tells us (the conclusions to know)1.13Calculating the cell emf1.14Cell notation (cell diagram)
3.1The electrolytic cell3.2Example: electrolysis of copper(II) chloride solution3.3First law3.4Second law3.5The faraday3.6The working formula3.7Worked examples3.8Electroplating3.9Extraction of aluminium3.10Electrorefining of copper3.11Galvanic cells versus electrolytic cells3.12Scientists and the value of electrochemistry
Chapter 5 - Organic Chemistry
0/721.1Historical background1.2Modern definition1.3Why are there so many organic compounds?1.4Comparison: organic and inorganic compounds1.5Molecular formula1.6Structural formula1.7Isomerism1.8Detecting carbon and hydrogen in an organic compound1.9Classification of hydrocarbons1.10Structure and the homologous series1.11Alkyl radicals (R–)1.12IUPAC nomenclature of alkanes1.13Methane — occurrence and preparation1.14Physical properties1.15Chemical properties of alkanes
5.1Functional groups5.2Alcohols and phenols — the difference5.3Nomenclature of alcohols5.4Classification of alcohols5.5Ethanol — preparation5.6Denatured (methylated) alcohol — "red spirit"5.7Physical properties5.8Chemical properties of ethanol5.9Uses of alcohols5.10Phenols5.11Preparation5.12Physical properties5.13Chemical properties5.14Tests for phenol
6.1The carboxyl group6.2Types6.3Nomenclature6.4Preparation of acetic acid6.5Physical properties6.6Chemical properties6.7Aromatic acids: benzoic acid6.8Important acids and their uses6.9Definition and formation6.10Nomenclature6.11Preparation6.12Physical properties6.13Chemical properties6.14Applications of esters6.15Aspirin6.16Types of organic reactions (summary)6.17Revision key points for Part B
7.1The birth of organic chemistry and the vital-force theory7.2Why organic compounds are so abundant7.3Organic versus inorganic compounds7.4Molecular formula, structural formula and isomers7.5Detecting carbon and hydrogen in an organic compound7.6Hydrocarbons and the alkane series7.7The alkyl radical and IUPAC naming7.8Methane, physical and chemical properties of alkanes7.9Practice with answers7.10Ministry exam traps
More lessons
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Text lesson
Lesson 6: Carboxylic Acids, Esters and Organic Polymers
Lesson 6: Carboxylic Acids, Esters and Organic Polymers
Overview
Overview
🌳 Concept tree
Lesson 6→Carboxylic Acids, Esters and Organic Polymers
├── The carboxyl group
├── Types
├── Nomenclature
├── Preparation of acetic acid
├── Physical properties
├── Chemical properties
├── Aromatic acids→benzoic acid
├── Important acids and their uses
├── Definition and formation
├── Nomenclature
├── Preparation
├── Physical properties
├── Chemical properties
├── Applications of esters
├── Aspirin
├── Types of organic reactions (summary)
└── Revision key points for Part B
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 1 / 19
The carboxyl group
The carboxyl group
- Carboxylic acids contain one or more carboxyl groups, –COOH (a carbonyl group C=O and a hydroxyl group –OH on the same carbon).
- They are the most acidic of the common organic compounds, but they are weak acids compared with mineral acids (HCl, H₂SO₄, HNO₃).
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| Aliphatic acids | –COOH attached to an alkyl group (R–COOH). Saturated mono-carboxylic aliphatic acids are called fatty acids because many occur in fats as esters with glycerol | COOHattachedalkylgroup |
| Aromatic acids | –COOH attached to a benzene ring (benzoic acid) | COOHattachedbenzenering |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 2 / 19
Types
Types
- Mono-carboxylic (monobasic) HCOOH formic acid, CH₃COOH acetic acid, C₆H₅COOH benzoic acid.
- Di-carboxylic (dibasic) HOOC–COOH oxalic acid; phthalic acid (benzene-1,2-dicarboxylic acid).
- Carboxylic acids are classed as aliphatic and aromatic.
- In aromatic acids such as benzoic acid, C₆H₅COOH, the carboxyl group is attached to a benzene ring.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 3 / 19
Nomenclature
Nomenclature
Common names come from the natural sourceformic (Latin formica, ant), acetic (acetum, vinegar), butyric (butyrum, butter), palmitic (palm oil).
IUPACthe alkane name with -e replaced by -oic acid; the carboxyl carbon is C-1:
| Formula | Common | IUPAC |
|---|---|---|
| HCOOH | formic acid | methanoic acid |
| CH₃COOH | acetic acid | ethanoic acid |
| CH₃CH₂CH₂COOH | butyric acid | butanoic acid |
| C₁₅H₃₁COOH | palmitic acid | hexadecanoic acid |
Substituents are numbered from the carboxyl carbon→2,2-dimethylbutanoic acid; 2,3-dichlorohexadecanoic acid; 2,4-dichlorobenzoic acid.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 4 / 19
Preparation of acetic acid
Preparation of acetic acid
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| Biological (vinegar) method |
| dilutealcoholicsolutionswine |
| From acetylene |
| catalytichydrationethynegives |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 5 / 19
Physical properties
Physical properties
- The first four members are corrosive liquids with a sharp, irritating smell, completely miscible with water.
- The middle members (C₅–C₉) are oily liquids with unpleasant odours and are only sparingly soluble; higher members (above C₁₀) are waxy, odourless solids and insoluble.
- Carboxylic acids boil at higher temperatures than alcohols of the same molecular mass because each pair of acid molecules is joined by two hydrogen bonds (a stable dimer):
| Acid | M | b.p. | Alcohol | M | b.p. |
|---|---|---|---|---|---|
| Methanoic | 46 | 100 °C | Ethanol | 46 | 78 °C |
| Ethanoic | 60 | 118 °C | 1-Propanol | 60 | 97–98 °C |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 6 / 19
Chemical properties
Chemical properties
1. Reactions of the hydrogen ion (acidity and salt formation).→React with:
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| active metals (above H) | 2CH₃COOH + Mg → (CH₃COO)₂Mg + H₂↑ | 2CH₃COOHCH₃COO |
| metal oxides and hydroxides | CH₃COOH + NaOH → CH₃COONa + H₂O | CH₃COOHNaOHCH₃COONa |
| carbonates and bicarbonates (with effervescence of CO₂) |
| CH₃COOHNaHCO₃CH₃COONa2CH₃COOH |
| 2. Reaction attributed to –OH: esterification |
| alcoholsconcH₂SO₄RCOOH |
| 3. Reaction of the carboxyl group: reduction. | Hydrogen with copper chromite (CuCrO₄/CuCr₂O₄) at 200 °C reduces the acid back to the alcohol (the reverse of oxidation of alcohols): CH₃COOH + 2H₂ → CH₃CH₂OH + H₂O | HydrogencopperchromiteCuCrO₄ |
- Detection of acetic acid:
- add sodium carbonate or bicarbonate — effervescence of CO₂ which turns lime water milky; it also gives the fruity ester smell when warmed with ethanol and a little conc.
- H₂SO₄.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 7 / 19
Aromatic acids: benzoic acid
Aromatic acids: benzoic acid
- Preparation oxidation of toluene by air at about 400 °C over vanadium pentoxide (V₂O₅) catalyst: C₆H₅CH₃ + 3[O] → C₆H₅COOH + H₂O (or by KMnO₄).
- Aromatic acids are generally stronger, less soluble in water and less volatile than aliphatic acids; they show the same reactions: C₆H₅COOH + NaOH → C₆H₅COONa + H₂O (sodium benzoate); C₆H₅COOH + C₂H₅OH (HCl or H₂SO₄) ⇌ C₆H₅COOC₂H₅ (ethyl benzoate) + H₂O.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 8 / 19
Important acids and their uses
Important acids and their uses
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| Formic acid (methanoic) |
| secretedantsdefencenettle |
| Acetic acid (ethanoic) |
| colourlesscorrosiveliquidpungent |
| Benzoic acid |
| sparinglysolublewatersodium |
| Citric acid |
| citrusfruitslemonorange |
| Lactic acid |
| CH₃CHCOOHsourmilk |
| Ascorbic acid (vitamin C) |
| neededsmallquantitiesfound |
| Salicylic acid |
| hydroxybenzoicbothCOOHused |
| Amino acids |
| derivativescarboxylicalkylgroup |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 9 / 19
Definition and formation
Definition and formation
- Esters are produced by the reaction of a carboxylic acid with an alcohol (esterification), with elimination of water:
- R–COOH + R′–OH ⇌ R–COO–R′ + H₂O
- Esters are widespread in nature and are responsible for the pleasant smell and taste of flowers and fruits.
- As the molecular mass of the acid and alcohol increases the odour decreases and the ester changes from a pleasant liquid to a nearly odourless waxy solid.
- Waxes (e.g.
- beeswax) are high-molecular-mass esters; fats and oils are esters of glycerol with long-chain fatty acids.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 10 / 19
Nomenclature
Nomenclature
- Name = (alkyl group of the alcohol) + (acid name with -ic acid → -ate):
HCOOCH₃ methyl formate (methyl methanoate)
CH₃COOC₂H₅ ethyl acetate (ethyl ethanoate)
C₆H₅COOC₂H₅ ethyl benzoate
- CH₃CH₂COOCH₃ methyl propanoate
- CH₃CH₂CH₂COOCH₃ methyl butanoate
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 11 / 19
Preparation
Preparation
Direct reaction of the acid with the alcohol→CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O. The reaction is reversible and slow, so it is heated with concentrated sulphuric acid (catalyst and dehydrating agent that removes water and shifts the equilibrium toward the ester) or with dry HCl gas.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 12 / 19
Physical properties
Physical properties
- Most esters are volatile liquids with pleasant odours.
- Their boiling points are much lower than those of the acids or alcohols of similar molecular mass, because esters have no –OH group and cannot form hydrogen bonds between their own molecules.
- For example (M = 60): ethanoic acid b.p. 118 °C, 1-propanol 97.8 °C, methyl formate 31.8 °C; (M = 74): propanoic acid 141 °C, butanol 118 °C, methyl ethanoate about 57 °C.
- For the same reason an ester is less soluble in water than the acid with the same number of carbon atoms.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 13 / 19
Chemical properties
Chemical properties
1. Hydrolysis→(the reverse of esterification) gives acid and alcohol.
- Acid hydrolysis (dilute mineral acid as catalyst, reversible): CH₃COOC₂H₅ + H₂O ⇌ CH₃COOH + C₂H₅OH.
- Alkaline hydrolysis — saponification (heating with aqueous NaOH or KOH; goes to completion): CH₃COOC₂H₅ + NaOH → CH₃COONa + C₂H₅OH; C₆H₅COOC₂H₅ + NaOH → C₆H₅COONa + C₂H₅OH. Called saponification because heating fats with alkali gives soap (sodium salts of long-chain fatty acids).
2. Ammonolysis: esters react with ammonia to give an acid amide and an alcohol: CH₃COOC₂H₅ + NH₃ → CH₃CONH₂ + C₂H₅OH.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 14 / 19
Applications of esters
Applications of esters
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| Flavours and perfumes |
| isobutylformatecherrypropyl |
| Fats and oils (triglycerides) |
| moleculeformedglycerolthree |
| Polyesters |
| condensationpolymersdibasicacid |
| Medicinal esters |
| aspirinacetylsalicylicacidmethyl |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 15 / 19
Aspirin
Aspirin
- Aspirin reduces pain, headache and fever, and also reduces blood clotting (helping prevent heart attacks).
- Adding the acetyl group to salicylic acid makes it less acidic and tasteless.
- In the body aspirin is hydrolysed back into salicylic acid and acetic acid; these acids irritate the stomach wall and can cause ulcers, so doctors advise crushing the tablet or dissolving it in water, and some aspirin tablets are mixed with an antacid such as aluminium hydroxide.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 16 / 19
Types of organic reactions (summary)
Types of organic reactions (summary)
| Type | Typical example |
|---|---|
| Substitution | CH₄ + Cl₂ → CH₃Cl + HCl; benzene nitration |
| Addition | ethene + Br₂; ethyne + HBr; benzene + H₂ |
| Elimination (dehydration) | ethanol → ethene + H₂O (180 °C) |
| Condensation | ester formation; phenol + HCHO → Bakelite |
| Oxidation / Reduction |
|
| Hydrolysis | ester + water; R–X + KOH |
| Polymerisation |
|
- Relation between families (conversion map):
- alkane ⇄ alkene ⇄ alkyne; alkene —(H₂O/H+)→ alcohol —[O]→ aldehyde (or ketone) —[O]→ acid; acid + alcohol ⇌ ester; alkyl halide ⇄ alcohol (KOH / HX); ethyne —(H₂O/Hg2+)→ ethanal.
Chemistry is a "two-edged sword"→the same knowledge gives medicines, fertilisers, plastics and fuels, but also explosives (TNT, nitroglycerine), CFCs that harm the ozone layer, and poisons; chemists therefore have a responsibility to use it for human benefit, and organic chemistry owes much to the efforts of scientists such as Wöhler, Kekulé and many others.
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 17 / 19
Revision key points for Part B
Revision key points for Part B
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| Alcohols |
| classifyoxidationproductsdehydration |
| Phenol |
| acidicalcoholsreactsNaOH |
| Acids |
| weakbondeddimersreact |
| Esters |
| pleasantsmellhydrolysissaponification |
| • |
| margin18pxbordersolid |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 18 / 19
Part 19
Part 19
- 📖
🔍 In-Depth Explanations, Deductions & Multi-Book Insights:
Chemistry Thanaweya Amma (2026/2027)
- Lesson 6 – Carboxylic Acids, Esters and Organic Polymers
- Detailed Academic Lesson Overview:
- Carboxylic acids contain the carboxyl group (-COOH) representing the highest organic acidity.
- Esters (-COO-) are formed by the reversible condensation between carboxylic acids and alcohols, characterized by sweet floral scents and forming fats, polyesters (Dacron), and aspirin.
🌳 Hierarchy Classification & Conceptual Roadmap
Carboxylic Acids and Esters
├── 1. Carboxylic Acids (Aliphatic & Aromatic)
│ ├── Acetic acid (Ethanoic acid CH3COOH)Prepared by bacterial oxidation of ethanol or oxidation of acetaldehyde
│ ├── Benzoic acid (C6H5COOH)Prepared by catalytic oxidation of toluene with V2O5 at 400°C
│ └── Acidity TestReacts with Na2CO3 or NaHCO3 with vigorous effervescence of CO2 gas
├── 2. Esterification and Properties of Esters
| Comparison aspect | Main idea | Keywords |
|---|---|---|
| • | │ ├── R-COOH + R'-OH ⇌ R-COO-R' + H2O (conc. H2SO4 removes water and prevents reverse reaction) | COOHconcH2SO4removes |
| │ └── Hydrolysis of Esters |
| Acidicreversesacidalcohol |
| • | └── 3. Critical Biological & Medical Applications | CriticalBiologicalMedicalApplications |
| ├── Polyesters (Dacron) | Condensation of Terephthalic acid with Ethylene glycol (arterial grafts) | CondensationTerephthalicacidEthylene |
| ├── Aspirin (Acetylsalicylic acid) | Formed by reacting Salicylic acid with Acetic acid (analgesic) | FormedreactingAceticanalgesic |
| └── Methyl Salicylate (Oil of Wintergreen) | Topical analgesic lotion for rheumatism | Topicalanalgesiclotionrheumatism |
| • | 📋 Master Teacher's Blackboard Rules & Exam Secrets | MasterTeacherBlackboardRules |
| RULE 1 |
| esterificationisotopictracerstudies |
| RULE 2 |
| Saponificationalkalinehydrolysisfats |
| RULE 3 |
| Aspirincontainsbothcarboxyl |
| 📊 Detailed Comparison Matrix | Medical Esters Derived from Salicylic Acid | MedicalEstersDerivedSalicylic |
| Medical Compound | Reactants Used | Active Functional Roles | Medical Therapeutic Use |
|---|---|---|---|
| Aspirin (Acetylsalicylic acid) | Salicylic acid (acting as phenol) + Acetic acid | Ester of acetic acid + Free -COOH group | Pain relief, fever reduction, anticoagulant |
| Oil of Wintergreen (Methyl salicylate) | Salicylic acid (acting as acid) + Methanol | Ester of salicylic acid + Free phenolic -OH | Topical skin analgesic for arthritis/muscle pain |
| Dacron Polyester | Terephthalic acid + Ethylene glycol | Condensation copolymer | Synthetic blood vessels and heart valves |
Lesson 6: Carboxylic Acids, Esters and Organic Polymers · 19 / 19
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