Titration is a quantitative analytical procedure to determine the concentration of an unknown solution (titrand/analyte) by adding a known concentration solution (titrant).
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).
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.
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.
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.
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.
Conduct titrations in triplicate for accuracy.
Average volume of titrant used to reach endpoint will be necessary for concentration calculations.
Mastery of proper titration techniques is essential.
Next video will focus on determining unknown acid concentration using a known base.
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