flask Acids & Bases
Acids and bases are everywhere — from stomach acid to soap to ocean chemistry. Learn the three acid-base models, master pH calculations, understand buffers that keep blood pH stable, and read titration curves.
What you will learn
- Compare Arrhenius, Brønsted–Lowry, and Lewis models
- Calculate pH and pOH
- Distinguish strong and weak acids
- Explain buffers
- Interpret titration curves
High School concepts
Three models of acids and bases
Compare the three acid-base models — Arrhenius, Brønsted–Lowry, and Lewis — and learn which to use for aqueous solutions, proton transfers, and electron-pair reactions.
Buffers: solutions that resist pH change
Learn what buffers are, how a weak acid and its conjugate base team up to resist pH change, and where buffers work in your body and daily life.
Conjugate acid-base pairs
Learn what conjugate acid-base pairs are, how to identify them, and the key rule: the stronger the acid, the weaker its conjugate base.
Acid-base indicators: color as a pH signal
Learn how acid-base indicators work, the color-change ranges of phenolphthalein, methyl orange, and litmus, and how to choose the right indicator for a titration.
The pH scale: measuring acidity
Learn what pH really measures, why the scale is logarithmic, how to calculate pH from [H⁺], and what the numbers mean in everyday life.
pOH: the other side of the scale
Learn what pOH measures, how it relates to pH through pH + pOH = 14, and how to convert between hydroxide concentration and pH.
Strong versus weak acids
Learn the difference between strong and weak acids: complete versus partial dissociation, the six strong acids to memorize, and why strength is not the same as concentration.
Acid-base titrations: finding the equivalence point
Learn what an acid-base titration is, how the equivalence point works, what titration curves look like, and how indicators signal the endpoint.
Introductory College concepts
The Henderson–Hasselbalch equation
Master the Henderson–Hasselbalch equation pH = pKa + log([A⁻]/[HA]): its derivation, how to use it, and its limits.
Ka and Kb: measuring acid and base strength
Learn what Ka and Kb measure, how to interconvert them with Kw = Ka·Kb, and why pKa is the convenient way to compare acid strengths.
Salt hydrolysis: why some salts change pH
Learn why some salt solutions are acidic, some basic, and some neutral — and how to predict which by looking at the parent acid and base.
Formulas
Calculators
Simulations
pH scale explorer
Dip a virtual pH probe into household solutions, change concentrations, and see how the pH scale responds in real time.
InteractiveAcid-base titration simulator
Add base to an acid drop by drop in this interactive simulation and watch the pH curve climb to the equivalence point.