Intro to Chemistry Chem1020 Lab. Titration and Buffers. Chemistry Department Minneapolis Community & Technical College. Overview. Part I Introduction Part II NaOH in the flask Part III HCl in the buret Part IV Titration Part V Calculation. Part I. Introduction.
NaOH in the flask
HCl in the buret
HA + B- A- + HB
Use a medicine dropper to transfer 10.00 ± 0.01 mL into a graduated cylinder.
Pour ~30mL into a beaker labeled as “Base”
Record this volume of NaOH solution.
Record this concentration of NaOH solution.
Add 2-3 drops of thymol blue.
Pour it into an Erlenmeyer flask.
Remove before starting the experiment, and put it back when all done.
Make sure it is secured by the buret clamp.
This buret has an incre-ment of 0.1 mL (why?), so all readings should go to the hundredth place with 2 decimal places.
It is used to collected all waste solutions. Empty into sink when all done.
Now it is in the “OFF” position.
Fill the buret with the help of a funnel to around the “0 mL” mark.
Pour ~30mL into a beaker labeled as “Acid”
Remove the funnel when done!!!
Open the valve to flush the bubbles into the “waste beaker”.
Check the buret bottom for bubbles.
Read the bottom of the meniscus again and record it as the “Final Reading”. This one should be recorded as 20.41 ± 0.01 mL.
Read the bottom of the meniscus in the buret and record it as the “Initial Reading”. E.g. the above volume should be recorded as 0.80 ± 0.01 mL.
Close the valve immediately after the solution turns yellow which indicates the completion of the reaction.
Put the NaOH solution under the buret and turn on the valve. Keep swirling the flask gently.
Make sure to read the buret both before and after the titration!!!
Empty the content in the Erlenmeyer flask into sink. Rinse the flask first with tap water followed by distilled water. No drying is needed.
Repeat steps 3-6 in slide #4 to get NaOH solution ready in the Erlenmeyer flask.
Repeat steps 2-4 in slide #6 to get HCl solution ready in the buret.
Repeat all steps in slide #7 for titration. To get a more accurate result this time, slow down by adding HCl dropwise when close to the endpoint.
Empty the contents in beakers and flask into sink. Rinse first with tap water followed by distilled water. Return everything to your bench.