Edited by Sarah Owoeye and Toluwalase Solanke
Titration is a method used in chemistry to determine the exact amount of an acid that will completely react with a base (or vice versa).
It involves gradually adding one solution to another until a chemical reaction is complete, usually indicated by a colour change.
You can think of titration as trying to balance a seesaw; adding one drop at a time until both sides are even. That is the point of balance or neutralisation.
Table of Contents
Principle Governing Titration
The principle behind titration is based on the concept of a neutralisation reaction, which occurs between an acid and a base. In this reaction:
Acid + Base → Salt + Water
When an acid and a base react in the correct ratio, they neutralise each other. The endpoint of the titration is reached when just enough of the standard solution (known as concentration) has been added to completely react with the unknown solution. This point is usually identified by a colour change caused by an indicator.
Also, the principle follows stoichiometry — that is, the mole ratio in the balanced chemical equation is used to calculate unknown concentrations or volumes.
Equipment You Will Need
To perform titration, you will need:
- A burette to hold the standard solution and add it drop by drop.
- A pipette to measure an accurate volume of the solution whose concentration is unknown.
- A conical flask where the reaction takes place.
- A white tile to make colour changes easier to see.
- A retort stand to hold the burette.
- An indicator to signal when the neutralisation has occurred.
Choosing An Indicator
The type of indicator you use depends on the strength of the acid and base:
- Phenolphthalein is ideal when titrating a strong base with a weak acid. It turns pink in bases and is colourless in acids.
- Methyl orange works best when titrating a strong acid with a weak base. It turns red in acids and yellow in bases.
Each indicator has a specific pH range where it changes colour, so choosing the correct one is important for accuracy.
Step-by-Step Process
- Use the pipette to measure a fixed amount of the unknown solution (usually a base) into the conical flask.
- Add a few drops of an appropriate indicator to the solution.
- Fill the burette with the acid (the solution with a known concentration).
- Record the initial volume on the burette.
- Slowly release the acid into the flask while gently swirling the flask to mix.
- Watch for a colour change — this is your endpoint.
- Record the final volume and calculate how much acid was used.
- Repeat the experiment until you get two or three readings that are nearly the same — these are called concordant titres.
Simple Titration Calculation Example
Let’s say 25 cm³ of sodium hydroxide is neutralised by 20 cm³ of 0.1 mol/dm³ hydrochloric acid.
Balanced equation:
NaOH + HCl → NaCl + H₂O
Using the formula:
C₁V₁ = C₂V₂ (because the mole ratio is 1:1)
That becomes:
0.1 × 20 = C × 25
C = (0.1 × 20) ÷ 25
C = 2 ÷ 25 = 0.08 mol/dm³
Why Titration Matters
Titration is widely used in labs and industries to:
- Measure how strong or weak a solution is.
- Ensure quality control in products like medicines, beverages, and water.
- Teach students precision and the practical application of chemical reactions.
Key Tips For Accuracy
- Rinse the burette, pipette, and conical flask properly before use.
- Make sure no air bubbles are trapped in the burette tip.
- Always read the burette at eye level and from the bottom of the liquid’s curve (the meniscus).
- Use just a few drops of indicator — more can affect results.
- Record and average two or more consistent readings
Final Thoughts
Titration is a scientific method used to determine the unknown concentration of a solution by reacting it with a known one. It is governed by the principles of neutralisation and stoichiometry, and requires careful measurement, observation, and calculations.
Read also: The Periodic Table: Understanding Trends and Patterns
