Post 3 Acid and Base

We did another vinegar lab that involved titrating KHP and vinegar samples using NaOH that turned the solution bright pink after mixing with phenolphthalein. It was the first time we used a buret, and it was difficult to control the drops, but regardless, it was a fun lab.
Here's the procedure:

 

1) Put on your splash-proof safety glasses, and keep them on throughout the lab.

2) Drain your buret into the waste beaker.

3) Rinse your buret with a small amount (several mL) of your NaOH solution, and drain into your waste beaker.

4) With the valve closed, add your NaOH solution until it is above the zero mark, and carefully drain until the meniscus is exactly at zero.

5) Obtain 0.5 – 0.8 gram of KHP, and record the mass to the nearest 0.001 g.

6) Transfer the KHP (without losing any) to the Erlenmeyer flask. Rinse the plastic tray with several mL of distilled water, and pour the rinse water into the Erlenmeyer. The goal is to transfer 100% of the KHP into the flask.

7) Add about 75 mL of water to the Erlenmeyer, and swirl to dissolve all of the KHP.

8) Add 2-3 drops of phenolphthalein.

9) Titrate the sample until a faint pink color remains, and record the volume of NaOH used to the nearest 0.1 mL.

10) Open up the vial with the blue cap. This vial contains commercial vinegar.

11) Pipet 10.00 mL of the vinegar into the Erlenmeyer flask. Dilute the volume to about 100 mL with distilled water, add two drops of phenolphthalein, and titrate with your NaOH solution. Record the volume of NaOH used.

12) If time permits, repeat steps 5-11.

13) Drain your buret, fill it with distilled water, and clean up you station.

Here's some websites that go over it.
khanacademy
chemwiki