Acid/Base Titration Chemistry: A Step by Step Guide (Part One- Strong Acids and Bases)

Acid–base titrations are one of the most common (and most tested) topics in chemistry — from high school and AP Chemistry to first-year university and even the MCAT.The good news? Once you understand the logic behind titrations, they become very systematic and predictable.

This guide breaks titrations down in a way that actually makes sense.

What Is an Acid–Base Titration?

An acid–base titration is a lab technique used to determine the unknown concentration of an acid or base by reacting it with a solution of known concentration.

In a titration:

• One solution (the titrant) is added slowly from a burette

• The other solution (the analyte) is in a flask

• The reaction continues until neutralization is reached

The key idea:

At the equivalence point, moles of acid = moles of base (after accounting for stoichiometry).

Key Terms You Must Know

1. Titrant vs Analyte

• Titrant: solution of known concentration (usually in the burette)

• Analyte: solution of unknown concentration (in the flask)

2. Equivalence Point

• The point where the acid and base have completely neutralized each other according to the balanced equation

• This is a stoichiometric point, not a color change

3. Endpoint

• The point where the indicator changes color

• Ideally very close to the equivalence point, but not always exactly the same

Strong Acid–Strong Base Titrations

Example:

• HCl + NaOH → NaCl + H₂O

Key features:

• pH starts low (acidic)

• pH rises gradually, then jumps sharply near equivalence

• Equivalence point pH = 7

Why?

• The salt formed (NaCl) does not affect pH

These are the simplest titrations and the foundation for understanding more complex ones.

Example- If you titrate 25.0 mL of 0.12 M HCl (analyte) with 0.15 M NaOH (titrant), at what volume of NaOH do you reach the equivalence point?

-Given: 25 mL (0.025 L- make sure you convert to L) and 0.12 M of HCl, 0.15 M of NaOH.

At the equivalence point- moles of strong acid = moles of strong base

Moles = concentration*volume

Based on the balanced equation= HCl is equivalent to the moles of NaOH

Moles of HCl= (0.025 L) (0.12 M)= 3*10^(-3) mol or 0.003 mol

Volume = moles/concentration so volume of NaOH = 0.003 mol/0.15 M= 0.02 L (20 mL).

Therefore, this titration reaches an equivalence point at 20 mL of titrant. pH at equivalence point (for a strong acid/base titration) = 7. At this point, all of the moles of acid have been neutralized by the moles of base!

Look out for Part 2- Weak Acid and Base Titrations coming soon!