82 articles
Acids, Bases & Salts
pH, strong and weak acids, buffers, titrations, indicators and salt chemistry.
Buffer Calculations: pH After Adding Acid or Base
Step-by-step method for calculating buffer pH before and after adding strong acid or strong base, with worked examples showing how little the pH changes, and what happens when a buffer is overwhelmed.
Buffer Capacity and Buffer Range
How much acid or base a buffer can absorb, why capacity depends on concentration and ratio, the pKa ± 1 buffer range, how to compare buffers numerically, and how to design one for a job.
Buffer Practice Problems
15 buffer practice problems with full solutions: pH from concentrations, buffers made by partial neutralisation, designing a buffer for a target pH, adding acid and base, dilution, capacity and blood.
The Common Ion Effect in Acid–Base Systems
How adding an ion that's already in an equilibrium suppresses a weak acid's or base's ionisation, with worked calculations, the link to buffers, and examples from drug absorption to water treatment.
The Henderson–Hasselbalch Equation with Worked Examples
Derive and use the Henderson–Hasselbalch equation: buffer pH from pKa and a ratio, finding the ratio needed for a target pH, buffers made by partial neutralisation, limits of the equation, and biology examples.
The Relationship Ka × Kb = Kw
Why the Ka of an acid and the Kb of its conjugate base always multiply to Kw, how to use pKa + pKb = 14, and worked examples on salt solutions, cyanide and ammonium.
Ka and pKa Practice Problems
15 practice problems on acid dissociation constants: converting Ka and pKa, ranking acid strength, finding Ka from pH, weak acid pH, percent ionisation, conjugate bases and species at a given pH, with worked answers.
Lewis Acids and Bases: Electron Pairs, Not Protons
The Lewis definition explained: acids accept electron pairs, bases donate them. Examples from BF₃ to metal ions, how to spot Lewis acids, and why this view matters in organic and inorganic chemistry.
Acid–Base Chemistry Without Water
How acids and bases behave in solvents like liquid ammonia, glacial ethanoic acid, sulfuric acid and molten salts: solvent self-ionisation, the solvent-system definition, levelling and differentiating solvents.
Percent Ionisation of Weak Acids
How to calculate the percentage of a weak acid that ionises, why dilution makes it rise, Ostwald's dilution law, and worked comparisons of acids like HF, methanoic and ethanoic acid.
Plotting a pH Curve with a pH Meter
A practical guide to recording a titration curve with a pH meter or data logger: method, a full sample data set for ethanoic acid, finding the equivalence point and pKa from the graph, derivative plots and evaluation.
pH of Weak Acids: ICE Tables and Approximations
How to calculate the pH of a weak acid using Ka and an ICE table, when the square-root shortcut is safe, when you need the quadratic, and how to work backwards from pH to Ka.
pH of Weak Bases Using Kb
Calculate the pH of weak bases like ammonia, amines and anions using Kb, an ICE table and pOH, including when to use the quadratic and how to get Kb from Ka.
Polyprotic Acids: Stepwise Dissociation
How acids with more than one acidic proton ionise one step at a time: Ka1, Ka2 and Ka3, why each step is weaker, the true pH of sulfuric acid, phosphate species and carbonic acid.
How to Prepare a Buffer Solution
Three practical methods for making a buffer of a chosen pH: mixing a weak acid with its salt, partial neutralisation, and mixing two salts. Includes calculations, lab steps, pH meter calibration and troubleshooting.
Salt Hydrolysis: Why Some Salts Are Acidic or Basic
Why dissolving a salt can change the pH of water: how cations and anions react with water, the four salt types, hydrated metal ions, and how to predict whether a salt solution is acidic, neutral or basic.
Salt Hydrolysis Practice Problems
12 practice problems on the pH of salt solutions: classifying salts, calculating pH with Ka and Kb, metal ion hydrolysis, amphiprotic salts, finding Ka from a salt's pH, and equivalence-point pH in titrations.
Superacids: Acids Stronger Than Pure Sulfuric Acid
What superacids are, how the Hammett acidity function measures acids beyond pH, famous examples from triflic acid to magic acid and fluoroantimonic acid, how they work, and why chemists use them.
Superbases: The Strongest Bases Known
What makes a base 'super', why hydroxide is the limit in water, and the chemistry of organolithiums, metal amides, hydrides, phosphazenes and the 'ortho-diethynylbenzene dianion', with their uses in synthesis.
Teaching Buffers Conceptually
A teacher's guide to buffers: building intuition before equations, a demonstration that makes buffering visible, the particle-level story, common misconceptions, Henderson–Hasselbalch scaffolding and biological contexts.
Titration Curves: Strong and Weak Combinations Explained
How pH changes during a titration for strong/strong, weak/strong, strong/weak and weak/weak pairs, with calculated key points, the buffer region, half-equivalence and indicator choice.
Buffers Explained: How Solutions Resist pH Change
What a buffer is, how it neutralizes added acid and base, the Henderson-Hasselbalch equation with worked examples, buffer capacity, and the buffer that keeps your blood at pH 7.4.