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ChemistryClass 12ICSE
Why Benzaldehyde Cannot Undergo an Aldol Reaction
Understand the mechanism of nucleophilic addition to aldehydes and ketones and why aldehydes react faster, then learn their condensation, oxidation and reduction reactions, including the aldol and Cannizzaro reactions.
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Why Fehling's Solution Turns Red With Ethanal but Not With Acetone
Name aldehydes and ketones and prepare them from alcohols, alkenes, alkynes, acid chlorides, nitriles and aromatic compounds, then use Tollens', Fehling's, iodoform and 2,4-DNP tests to tell them apart.
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Why Diethyl Ether Boils Far Lower Than Butanol Despite the Same Formula
Name ethers and prepare them by Williamson's synthesis, then understand their low boiling points, their cleavage by hydrogen halides and the electrophilic substitution reactions of aromatic ethers such as anisole.
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Why Picric Acid Is Far More Acidic Than Phenol
Understand why phenols are acidic and how substituents raise or lower their acidity, and learn the electrophilic substitution reactions of phenol, including bromination, nitration and Kolbe's reaction.
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Why Heating Ethanol With Acid Can Give Either Ethene or Ether
Name and prepare primary, secondary and tertiary alcohols, understand their dehydration and esterification reactions, and use chemical tests such as the Lucas test and oxidation to tell the three classes apart.
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Why Chlorobenzene Refuses to React Like Chloroethane
Understand why haloarenes resist nucleophilic substitution, how haloalkanes undergo elimination to form alkenes, and the properties and uses of chloroform, iodoform and DDT.
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Why a Crowded Carbon Changes How a Haloalkane Reacts
Name and classify haloalkanes, prepare them from alcohols, alkenes and halogen exchange, and understand the SN1 and SN2 mechanisms of nucleophilic substitution and the factors that decide between them.
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Why the Same Iron Ion Can Have One or Five Unpaired Electrons
Explain bonding in coordination compounds with valence bond theory and crystal field theory, relate crystal field splitting to the colour and magnetic properties of complexes, and calculate crystal field stabilisation energy.
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Why Cisplatin Fights Cancer but Its Twin Transplatin Does Not
Identify and distinguish structural isomerism — ionisation, linkage, coordination and hydrate — and stereoisomerism, including geometrical and optical isomerism, in coordination compounds, and learn to count isomers.
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Why Silver Nitrate Pulls Out Only Some of the Chloride in a Cobalt Complex
Apply IUPAC rules to name coordination compounds, understand Werner's theory of primary and secondary valence, define ligands, coordination number and coordination sphere, and calculate effective atomic numbers.
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Why Zirconium and Hafnium Are Almost Impossible to Tell Apart
Understand the cause of lanthanoid contraction and its consequences for the heavier transition metals and the lanthanoids themselves, and compare the configurations, oxidation states and properties of lanthanoids and actinoids.
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Why Orange Dichromate Turns Green When It Oxidises Something
Learn how potassium dichromate and potassium permanganate are prepared from their ores, their structures and properties, how their oxidising action changes with the medium, and how to find their equivalent masses in titrations.
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Why Transition Metals Show So Many Oxidation States
Understand the electronic configuration of the 3d transition series and the trends it produces — variable oxidation states, catalytic behaviour, coloured ions and paramagnetism — and calculate spin-only magnetic moments.
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Why a Small Rise in Temperature Can Double a Reaction's Rate
Understand collision theory and the conditions for effective collisions, use the Arrhenius equation to calculate activation energy from rate constants at two temperatures, and see how catalysts speed up reactions.
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Why Doubling One Reactant Can Quadruple a Reaction's Speed
Define the rate of reaction and write rate laws, find order and molecularity from experimental data, and distinguish zero-order, first-order and pseudo-first-order reactions with their integrated equations and half-lives.
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Why a Car Battery Can Be Recharged but a Torch Cell Cannot
Define molar and equivalent conductivity and explain how they change with concentration using Kohlrausch's law, learn how the dry cell, lead storage battery and fuel cells work, and understand corrosion as an electrochemical process.
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How Much Silver Coats a Spoon When Current Flows for One Hour?
Apply the Nernst equation to find cell emf at non-standard concentrations, link emf to Gibbs energy and the equilibrium constant, and solve electrolysis problems with Faraday's first and second laws.
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Why a Silver Spoon Is Safe in Copper Sulphate but an Iron Nail Is Not
Understand how a galvanic cell such as the Daniell cell is built and how it works, write standard cell notation, and use standard electrode potentials and the electrochemical series to predict whether redox reactions are feasible.
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Why Kulfi Sellers Pack Salt Into the Ice Around Their Moulds
Explain and calculate the four colligative properties — lowering of vapour pressure, boiling point elevation, freezing point depression and osmotic pressure — and use the van't Hoff factor for solutes that dissociate or associate.
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Why Deep-Sea Divers Risk the Bends When They Surface Too Fast
Express the concentration of solutions in molarity, molality, mole fraction and normality, apply Raoult's law to ideal and non-ideal solutions, and use Henry's law to explain how gases dissolve in liquids.
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How Fertiliser From Farms Can Turn a Lake Green and Lifeless
Learn the major water and soil pollutants and where they come from, including eutrophication, BOD and biomagnification, and how the principles of green chemistry prevent pollution at its source.
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Why Winter Mornings in North Indian Cities Turn Grey With Smog
Understand the causes and effects of tropospheric pollution, including classical and photochemical smog, acid rain and the greenhouse effect, and how CFCs deplete the ozone layer in the stratosphere.
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Why Toluene Reacts Faster Than Benzene but Nitrobenzene Is Sluggish
Explain the structure and aromaticity of benzene using resonance and Huckel's rule, follow the mechanism of electrophilic aromatic substitution in nitration, halogenation and Friedel-Crafts reactions, and predict directing effects.
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Why Ethyne Can Lose a Hydrogen Like an Acid but Ethene Cannot
Name alkynes and prepare them from calcium carbide and vicinal dihalides, understand why terminal alkynes are acidic, and learn the addition reactions of alkynes with hydrogen, halogens, hydrogen halides and water.
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