titration

Introduction to Titration

• Titration is a quantitative analytical procedure to determine the concentration of an unknown solution (titrand/analyte) by adding a known concentration solution (titrant).

Equipment Needed for Titration

• Carolina's Complete Burette Assembly:

  • Includes: burette, ring stand, and burette clamp.

• Burette:

  • Long narrow graduated tube used to add titrant.

  • Stopcock regulates flow of liquid.

  • Markings go from lowest (top) to highest (bottom).

• Ring Stand and Burette Clamp:

  • Used to mount and secure the burette.

• Additional Materials:

  • Small funnel (for filling the burette).

  • 125 mL Erlenmeyer flask (preferred for titrations due to vigorous swirling capability).

  • Volumetric pipette and pipette bulb (to transfer analyte).

  • Wash bottle with deionized water.

  • Beaker/flask containing titrant and analyte.

  • Appropriate indicators for the reaction.

  • Reading card for meniscus measurement.

  • White paper (to enhance endpoint visibility).

Preparing the Burette

• Rinse burette with deionized water, followed by a small amount of titrant.

• Open stopcock to drain rinsate; repeat if necessary to ensure clean walls.

• Mount burette vertically in the clamp, ensuring flask fits beneath.

• Fill burette with titrant, checking for air bubbles before removing funnel.

Volume Measurement

• Record starting volume after ensuring no air bubbles are present in the burette tip.

• Read meniscus at eye level from the bottom of the curvature.

• Record to the nearest hundredth of a milliliter for accuracy.

• Use the volumetric pipette to transfer analyte into the flask and add indicator.

Mechanism of Titration

• Operate burette with one hand (stopcock) while swirling flask with the other.

• First titration is generally an estimate:

  • Open stopcock to allow rapid flow of titrant while continuously swirling.

  • Watch for the appearance and disappearance of indicator color.

• When color changes, close stopcock and record final volume.

• Subtract initial from final volume for estimated titrant volume needed.

Adjusting the Titration Approach

• Note: an excess of titrant results in a dark solution; endpoint is a faintly colored analyte.

• Slow down titrant addition as the endpoint approaches:

  • Adjust stopcock to a dropwise flow when noticing color changes.

  • Continue swirling and close stopcock when the indicator color takes longer to fade.

  • Rinse burette tip with deionized water.

• Record final volume to confirm endpoint is reached predominately by faint color.

• Repeat drop-wise addition if analyte remains colorless before confirming.

Repetition and Calculation of Results

• Conduct titrations in triplicate for accuracy.

• Average volume of titrant used to reach endpoint will be necessary for concentration calculations.

Conclusion and Next Steps

• Mastery of proper titration techniques is essential.

• Next video will focus on determining unknown acid concentration using a known base.

• Explore CarolinaChemistry.com for laboratory products and kits.