ChemistryChemical Kinetics· Class 12
Collision theory
“Most collisions bounce off harmlessly; only the right ones react.”
Reactions occur when particles collide with enough energy and correct orientation.
Memory trick: Energy + orientation.
Fundamentals
1,200 must-knows for NEET & JEE
The core facts every aspirant should own — each a titled nugget with a real-world story, the concept in plain words, and a memory trick. Works even when the internet doesn't.
300 fundamentals
ChemistryChemical Kinetics· Class 12
Pseudo first-order reaction
“Sugar hydrolysis looks first-order because water is overwhelmingly abundant.”
A higher-order reaction that behaves as first-order because one reactant is in large excess.
Memory trick: Excess reactant hides its order.
ChemistryChemical Kinetics· Class 12
Rate-determining step
“A reaction is only as fast as its slowest bottleneck.”
The slowest step in a mechanism sets the overall reaction rate.
Memory trick: Slowest step rules the rate.
ChemistryStates of Matter· Class 11
Critical temperature
“You can't squeeze oxygen into liquid at room temperature — you must cool it first.”
Above it, a gas cannot be liquefied by pressure alone.
Memory trick: Above it, no liquefaction.
ChemistryChemical Bonding & Molecular Structure· Class 11
Formal charge
“It helps pick which Lewis structure nature actually prefers.”
Bookkeeping charge on an atom in a Lewis structure, guiding the best structure.
Memory trick: Lowest formal charges win.
ChemistryChemical Bonding & Molecular Structure· Class 11
Fajans' rules
“They explain why some 'ionic' compounds behave partly covalent.”
Small, highly charged ions give bonds more covalent character.
Memory trick: Small + high charge → covalent.
ChemistryChemical Bonding & Molecular Structure· Class 11
Molecular orbital theory: O₂ is paramagnetic
“The theory that finally explained why oxygen sticks to a magnet.”
MOT correctly predicts O₂ has two unpaired electrons, so liquid oxygen is attracted to a magnet.
Memory trick: O₂ has unpaired electrons.
ChemistryOrganic Chemistry — Basic Concepts· Class 11
Hyperconjugation
“The 'no-bond resonance' that steadies carbocations and alkenes.”
Stabilisation from overlap of a σ-bond with an adjacent empty or partly filled orbital.
Memory trick: σ-electrons lend stability.
ChemistryOrganic Chemistry — Basic Concepts· Class 12
Chirality
“One mirror-form of a drug can heal while the other harms.”
A molecule that can't be superimposed on its mirror image is chiral, like your hands.
Memory trick: Non-superimposable mirror images.
ChemistryAldehydes, Ketones & Carboxylic Acids· Class 12
Tautomerism
“Keto and enol forms flip back and forth in many carbonyl compounds.”
A molecule rapidly interconverts between structural isomers, usually by shifting an H.
Memory trick: H hops between two forms.
ChemistryThe p-Block Elements· Class 12
Haber process
“This reaction feeds roughly half the world's population.”
N₂ + 3H₂ ⇌ 2NH₃ over an iron catalyst makes ammonia for fertilisers.
N₂+3H₂⇌2NH₃
Memory trick: Iron catalyst, high pressure.
ChemistryThe p-Block Elements· Class 12
Contact process
“Sulphuric acid is the most-produced industrial chemical on Earth.”
Industrial sulphuric acid is made by oxidising SO₂ to SO₃ over a V₂O₅ catalyst.
Memory trick: V₂O₅ catalyst.
ChemistryThe p-Block Elements· Class 12
Ostwald process
“It turns ammonia into the acid behind fertilisers and explosives.”
Nitric acid is made by catalytically oxidising ammonia.
Memory trick: NH₃ → HNO₃.
ChemistryHydrogen· Class 11
Hydrogen peroxide
“It fizzes on a cut as it releases oxygen.”
A pale blue liquid, a strong oxidiser used as a bleach and antiseptic.
H₂O₂
Memory trick: Oxidiser and bleach.
ChemistryHydrogen· Class 11
Hard vs soft water
“Hard water leaves scum and scales up kettles.”
Hard water contains Ca²⁺/Mg²⁺ ions that stop soap from lathering.
Memory trick: Ca/Mg ions = hardness.
ChemistryThe p-Block Elements· Class 12
Interhalogen compounds
“Mixing halogens makes fiercely reactive hybrids.”
Compounds between two different halogens (e.g. ICl), generally more reactive than the parent halogens.
Memory trick: Halogen + halogen.
ChemistryCoordination Compounds· Class 12
Crystal field splitting
“The exact split decides whether a gemstone glows red or green.”
Ligands split a metal's d-orbitals in energy, explaining complex colour and magnetism.
Memory trick: Ligands split the d-orbitals.
ChemistryCoordination Compounds· Class 12
Spectrochemical series
“Strong-field ligands can force electrons to pair up.”
Ligands ranked by how strongly they split d-orbitals.
Memory trick: Strong vs weak field ligands.
ChemistryCoordination Compounds· Class 12
Isomerism in complexes
“Cisplatin fights cancer, but its trans isomer doesn't — shape is everything.”
Coordination compounds show geometrical, optical and linkage isomerism.
Memory trick: Same formula, different arrangement.
ChemistryAldehydes, Ketones & Carboxylic Acids· Class 12
Grignard reagent
“A chemist's power tool for stitching carbon skeletons together.”
R–MgX reacts with carbonyls to build new carbon–carbon bonds.
Memory trick: Adds R to C=O.
ChemistryHydrocarbons· Class 11
Ozonolysis
“It's a molecular knife that shows exactly where the double bond sat.”
Ozone cleaves a C=C double bond, revealing where it was located.
Memory trick: Cuts at the C=C.
ChemistryAldehydes, Ketones & Carboxylic Acids· Class 12
Tollens' test
“A gleaming silver coating on the tube flags an aldehyde.”
Aldehydes reduce Tollens' reagent to deposit a silver mirror; ketones don't.
Memory trick: Silver mirror = aldehyde.
ChemistryAldehydes, Ketones & Carboxylic Acids· Class 12
Iodoform test
“A yellow crystal and antiseptic smell reveal a CH₃CO group.”
Methyl ketones and ethanol give a yellow iodoform precipitate.
Memory trick: Yellow ppt → CH₃CO group.
ChemistryAldehydes, Ketones & Carboxylic Acids· Class 12
Esterification is reversible
“Le Chatelier turns a reversible reaction into a productive one.”
Acid + alcohol ⇌ ester + water; removing water drives it forward.
Memory trick: Remove water → more ester.