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.

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