Modified Procedure for Experiment 26(1st Week)

A.Preparation of Reaction Mixture

In a dry, clean 125-mL Erlenmeyer flask, place:

19 mL n-propanol

14 mL acetic acid

Cover flask with a rubber stopper covered in saran wrap. This is your reaction mixture. DO NOT ADD H2SO4 YET UNTIL AFTER YOU ARE THROUGH WITH THE TITRATION.

Note: Try to measure the liquids as accurately as possible using clean, dry graduated cylinders.

  1. Determination of Acetic Acid concentration in reaction mixture
  1. Using a pipet and bulb, measure 1 mL of previously prepared reaction mixture into a clean, dry 250-mL erlenmeyer flask.
  2. To the same 250-mL erlenmeyer flask, add 100 mL of distilled water (measured with a grad. Cylinder).
  3. Add 2 drops of phenolphthalein to the flask.
  4. Titrate the solution with 0.1 M NaOH. Use the exact molarity of NaOH for your calculations. Remember, the endpoint should be a light pink color that stays for about 5 seconds. Do not go for the fuschia endpoint which indicates that you have added too much NaOH.
  5. Repeat procedure for a second trial.
  6. Discardtitrated solutions in the sink when you’re done.

Calculation:Mole acetic acid = Mole of NaOH

(MV) Acetic acid=(MV) NaOH

(M) (1 mL)acetic acid=(0.1 M) (V)NaOH

7.Addition of Catalyst:

Once you’re done with the titration, add 10 drops of 6 M concentrated H2SO4 to your reaction mixture prepared in Part A. Re-stopper and set aside on the designated bookshelf. You will work on this mixture when you come back in 2 weeks.

C.Preparation of a blank solution

Purpose: The purpose of preparing a blank is to determine how much of the NaOH will be neutralized solely by H2SO4, which will be used as the catalyst in the reaction. Because the reaction proceeds as soon as the reactants are mixed together and because NaOH reacts with both acids, CH3COOH andH2SO4, it is essential to determine how much of the NaOH will be neutralized solely by H2SO4. Next week, you will again titrate the solution with NaOH to determine how much acetic acid is left. If this is known, the amount of NaOH neutralized by CH3COOH can easily be determined.

  1. In a 150-mL beaker, place “31” mL distilled water and 10 drops of 6M H2SO4. If less than 31 mL are left in Part A, modify volume for Part C.
  2. Pipet 1-mL of this solution into a 250-mL flask containing 100 mL distilled water.
  3. Add 2 drops phenolphthalein. Titrate with 0.1 M NaOH. Note exact molarity of NaOH.
  4. Repeat procedure for a second trial.
  5. Toss solutions when you’re done.