How to Do a Titration

Titrations are a way to determine exactly when a reaction ends to figure out how much of a reactant is in the solution. During a titration, a burette drips one of the reactants, whose concentration is known, into a solution whose concentration is unknown. All that is needed to be known is whether the unknown solution is acidic or basic.

Things You'll Need

• Acidic or basic solution of unknown concentration
• Acidic or basic solution of known concentration (must be opposite pH of the unknown concentration)
• Burette
• Indicator

Instructions

1. Prepare the setup by placing the solution of unknown concentration in the beaker and the known solution in the burette. Record the volume of both the solution in the beaker and the solution in the burette.

2. Add the indicator to the solution. When the solution turns a light pink, the reaction is complete.

3. Drip the solution slowly into the beaker containing the unknown solution. As you get closer to completing the reaction, allow drips to fall one at a time.

4. When the solution turns a light pink, the reaction is complete. At this point, determine how much of the known solution has been used by subtracting the amount that is left in the burette from the original amount.

5. Multiply the concentration of the known solution times the volume used. Then multiply by the volume of the unknown solution. This will give you the concentration of the unknown solution. For example, if you used 1 milliliter of a 0.5 M base to neutralize 2 milliliters of the acid, multiple 0.5 times 1 to get 0.5 and then multiply by 2 to get 1.0 M. 1.0 M is the concentration of the unknown acid.

Tips & Warnings

• It is very easy to use too much of the known solution. If you are unsure if the reaction has neutralized, record the volume used and add a partial drop. If the solution turns bright pink, use the recorded volume.

• Always use caution when handling acids.

References

• Titration Techniques