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482 published articles from Calculator Knowledge Base on 4ab.in — one place for every post.
ConceptsAdsorption in Water Purification — Freundlich and Langmuir Isotherms at WorkHow the Freundlich and Langmuir isotherms from your surface chemistry chapter are used to size activated carbon for water treatment. Four worked calculations including the log-log 23 Sep 2026 · 8 min read
ConceptsAllotropy — Carbon, Sulphur and Phosphorus ComparedAllotropy explained for Class 11-12: diamond vs graphite vs fullerene, rhombic and monoclinic sulphur, white red and black phosphorus, with molar mass and molar volume working and 26 Sep 2026 · 9 min read
ConceptsAlternate Routes After an Unsuccessful Attempt — A Chemistry Decision MapDid not clear CSIR-NET, GATE or IIT-JAM this cycle? A practical map of every route still open — reattempt, other qualifying exams, institute entrance tests…18 Sep 2026 · 8 min read
EquilibriumAmphoteric Substances — Acting as Both Acid and BaseAmphoteric and amphiprotic explained: water, ZnO, Al2O3 and Al(OH)3 equations both ways, the pH of NaHCO3 from pKa1 and pKa2, amino acid isoelectric points and the periodic trend i25 Sep 2026 · 7 min read
CareersAnalytical Chemistry as a Career Route — What the Work Actually InvolvesA practical look at analytical chemistry careers — instrumentation, method development, QC vs R&D analytical work, entry routes and the skills that actually get you hired.27 Sep 2026 · 7 min read
ConceptsAngle Conversions — Degrees, Radians and GradiansConverting between degrees, radians and gradians — the formulas, why calculators have a DEG/RAD/GRAD mode at all, and the worked examples that make it stick.04 Oct 2026 · 3 min read
ElectrochemistryAromaticity and Hückel's Rule — How to Count π ElectronsThe four conditions for aromaticity, how to count pi electrons correctly including lone pairs and carbocations, aromatic vs antiaromatic vs non-aromatic…19 Sep 2026 · 9 min read
OrganicAromaticity Beyond Benzene — Antiaromaticity and the ExceptionsCharged aromatic ions, antiaromatic cyclobutadiene, heteroaromatic lone-pair rules, and Möbius aromaticity — the postgraduate exceptions to Hückel29 Sep 2026 · 8 min read
Exam guidesBalancing a Part-Time Job with Postgraduate StudyPractical, honest guidance for chemistry postgraduates working a part-time job alongside MSc or research study — choosing compatible work, managing time, and avoiding burnout.05 Oct 2026 · 5 min read
Exam guidesBalancing JEE/NEET Foundation Prep With Class 11 School ChemistrySchool chemistry and entrance-exam foundation prep are not two subjects competing for the same hours. A practical weekly split, and the trap of racing coaching ahead of the syllabu28 Sep 2026 · 5 min read
ConceptsBMI Formula — What It Does and Does Not Tell YouThe BMI formula worked step by step in metric and imperial units, the standard categories, the unit mistake that ruins the answer, and the real limits of the number.24 Sep 2026 · 5 min read
Quantum & structureBohr Model — Radius and Energy of the nth Orbitr = 0.529 n²/Z Å and E = −13.6 Z²/n² eV explained, with four worked examples: hydrogen n = 3, He⁺, the red hydrogen line checked against Rydberg, and ionisation energy in eV and kJ23 Sep 2026 · 7 min read
ConceptsBoiling Point Elevation — Worked Problems and FormulaBoiling point elevation explained with delta Tb = i Kb m, worked problems for glucose, an unknown solute in chloroform and NaCl, where Kb comes from, and…19 Sep 2026 · 6 min read
EquilibriumBuffer Chemistry in Blood and Physiology — Henderson–Hasselbalch at WorkHow the Henderson–Hasselbalch equation you learnt for acetate buffers explains blood pH, why the bicarbonate system uses an apparent pKa of 6.1, three fully worked calculations, an21 Sep 2026 · 7 min read
EquilibriumBuffer Systems in Industrial Fermentation and BiotechnologyHow the Henderson-Hasselbalch equation and buffer capacity keep a fermenter04 Oct 2026 · 5 min read
ConceptsBuilding a CV as a Chemistry Postgraduate — What to Put In and What to CutHow to write a chemistry CV that survives a real shortlisting: the sections that matter, how to describe techniques and your dissertation honestly, before-and-after bullet rewrites20 Sep 2026 · 8 min read
ConceptsCapacitors in Series and ParallelCapacitors in series and parallel worked step by step: equivalent capacitance, charge and voltage across each capacitor, and why the rules are the exact opposite of resistors.30 Sep 2026 · 4 min read
OrganicCarbene and Nitrene Chemistry — Singlet vs Triplet, Generation and ReactionsCarbenes and nitrenes for IIT-JAM, GATE and CSIR-NET: singlet and triplet electronic states with term symbols and geometries, substituent control, generation routes, stereospecific22 Sep 2026 · 10 min read
OrganicCatalysis and Kinetics in Polymer ManufacturingHow catalyst choice controls polymer chain growth and stereochemistry, with the Carothers equation worked through for step-growth polymerisation and a turnover-frequency calculatio30 Sep 2026 · 6 min read
InorganicThe Chelate Effect in Coordination ChemistryWhy polydentate ligands like ethylenediamine and EDTA form far more stable metal complexes than monodentate ligands do — the entropy-driven chelate effect explained with worked com29 Sep 2026 · 5 min read
KineticsChemical Kinetics in Pharmaceutical Stability TestingHow zero-order and first-order degradation kinetics set a drug02 Oct 2026 · 5 min read
ConceptsChemistry Consulting and Technical Sales RolesWhat technical sales, application science and consulting roles actually involve for a chemistry graduate — the real skills, the daily work, and the misconceptions about these caree02 Oct 2026 · 5 min read
ConceptsChemistry Entrepreneurship — The Realistic VersionWhat starting a chemistry business in India actually involves: which businesses are asset-light and which are not, the approvals that gate each one, how to work out your own cost p25 Sep 2026 · 9 min read
ConceptsChemistry in Government Scientific Services — Where Chemists Actually WorkThe government organisations in India that employ chemists, what the work involves in each, and the recruitment routes — institutional advertisements, national examinations and pro22 Sep 2026 · 9 min read
ConceptsChemistry for a Medicine Aspirant vs an Engineering AspirantSame Class 11-12 chemistry syllabus, two different targets. How a medicine aspirant and an engineering aspirant should study chemistry differently, with…19 Sep 2026 · 7 min read
ConceptsChemistry, Patents and Intellectual-Property WorkWhat patent and IP work for a chemistry graduate actually involves — reading specifications, prior-art searching, drafting support, the patent agent route, and the skills that matt29 Sep 2026 · 6 min read
ConceptsChoosing a Reference Book Without Overloading YourselfThe question is not "which book is best" but "what gap does my textbook leave". A gap-first framework for picking one reference book that actually gets used.02 Oct 2026 · 5 min read
ConceptsChoosing a Research Supervisor — How to Judge a Group Before You JoinThe supervisor matters more than the institute19 Sep 2026 · 9 min read
ConceptsChoosing Between PCM and PCB — An Honest ComparisonPCM or PCB after Class 10? What each stream leads to, a scored decision worksheet, the PCMB option and changing your mind later — an honest comparison.20 Sep 2026 · 7 min read
CareersChoosing Between a Research-Focused and an Industry-Focused MScHow research-oriented and industry/practical-oriented chemistry MSc programmes actually differ, what questions to ask before choosing, and how to judge a programme honestly.03 Oct 2026 · 5 min read
ConceptsCircular Motion and Centripetal Forcev = ωr, a = v²/r and F = mv²/r worked in full — a whirling stone, a car on a bend, a vertical loop and the Moon, each answer checked a second way.26 Sep 2026 · 7 min read
InorganicClass 10 Periodic Classification of Elements — Mendeleev to the Modern TableNCERT Class 10 chapter guide to periodic classification — Dobereiner28 Sep 2026 · 6 min read
ConceptsCoping With the Class 10 to Class 11 Jump in ChemistryWhy chemistry marks fall in the first term of Class 11, the four separate walls behind that fall — quantitative, mathematical, abstract and volume — and how to work out which one i22 Sep 2026 · 7 min read
InorganicClass 11 Classification of Elements and Periodicity in PropertiesNCERT Class 11 chapter guide to classification of elements and periodicity — s/p/d/f blocks, IUPAC element naming, and quantified trends in ionisation enthalpy and atomic radius.05 Oct 2026 · 5 min read
InorganicClass 11 Hydrogen and the s-Block Elements — NCERT Chapter GuideNCERT Class 11 chapter guide to hydrogen (isotopes, hydrides, heavy water) and the s-block elements — alkali and alkaline earth metals, trends, flame tests and worked examples.27 Sep 2026 · 6 min read
EquilibriumClass 11 Ionic Equilibrium — the Seven Problem TypesClass 11 ionic equilibrium sorted into seven problem types: strong acid pH, weak acid pH and degree of dissociation, common ion effect, buffers, salt hydrolysis, Ksp and solubility26 Sep 2026 · 8 min read
OrganicClass 11 Organic Chemistry — Basic Principles and TechniquesNCERT Class 11 chapter guide to purification methods and qualitative/quantitative analysis of organic compounds — Lassaigne04 Oct 2026 · 6 min read
ElectrochemistryClass 11 Redox: NCERT Question PatternsThe six redox question patterns in Class 11 NCERT: oxidation numbers, fractional values, oxidising agents, disproportionation, with worked examples.12 Oct 2026 · 5 min read
SolutionsClass 12 Biomolecules — The Structures Worth KnowingClass 12 biomolecules made clear: glucose and fructose structures, reducing vs non-reducing sugars, starch and cellulose linkages, amino acids and protein…18 Sep 2026 · 10 min read
ConceptsClass 12 Chemistry in Everyday Life — Drugs, Food and Cleansing AgentsClass 12 Chemistry in Everyday Life explained: drug classification, antacids, antibiotics vs antiseptics vs disinfectants, artificial sweeteners, antioxidants, soaps and detergents20 Sep 2026 · 11 min read
InorganicClass 12 General Principles of Isolation of Elements — MetallurgyNCERT Class 12 metallurgy chapter guide — concentration of ores, Ellingham diagrams, reduction and refining methods, with Gibbs energy and Faraday03 Oct 2026 · 6 min read
OrganicClass 12 Polymers — Types, Preparation and Degree of PolymerisationClass 12 polymers explained: classification by source, structure, mode of polymerisation and molecular forces; addition vs condensation; monomers of nylon…19 Sep 2026 · 9 min read
ConceptsClass 12 Surface Chemistry — Adsorption and ColloidsNCERT Class 12 surface chemistry made clear: adsorption vs absorption, physisorption vs chemisorption, the Freundlich isotherm with worked numericals, catalysis, colloid types, Tyn24 Sep 2026 · 11 min read
SolutionsClass 9 Atoms and Molecules — the Laws of Chemical Combination ExplainedClass 9 atoms and molecules made clear: law of conservation of mass, law of constant proportions, Dalton23 Sep 2026 · 8 min read
ConceptsClass 9 — Is Matter Around Us Pure? Mixtures and SeparationNCERT Class 9 chapter guide to mixtures, solutions, suspensions and colloids, and the correct separation technique for each — with concentration numericals worked in full.02 Oct 2026 · 5 min read
ConceptsClass 9 Matter in Our Surroundings — States and Changes of StateNCERT Class 9 chapter guide to matter in our surroundings — the particle nature of matter, the three states, latent heat, evaporation and sublimation, with worked examples.01 Oct 2026 · 5 min read
ElectrochemistryClass 9 Structure of the Atom — Models, Particles and Electron DistributionNCERT Class 9 chapter guide to the structure of the atom — Thomson, Rutherford and Bohr30 Sep 2026 · 5 min read
OrganicClick Chemistry and Bioorthogonal ReactionsSharpless02 Oct 2026 · 6 min read