Name: ______Date: ______

TITRATION LAB

DETERMINE THE MOLAR CONCENTRATION OF ACETIC ACID USING A STRONG BASE

1.  Diluting stock solution:

Commercially available vinegar is a solution of acetic acid, CH3COOH, in water. Acetic acid is a weak acid.

Your task is to dilute the stock vinegar ) into a solution that is 10x more diluted than the stock solution

Lab summary:

Chemical formula/name / Their concentrations (mol/L) are:
What is the titrant used in today’s lab?
What is the analyte used in today’s lab?
What is the indicator used in today’s lab? / phenopthalein

2. Demonstrate your understanding of apparatus set up by labelling the diagram below. Please note

·  where will you put NaOH? ______

·  where will you put the vinegar?______

·  where will the indicator be added to?______

I.  MATERIALS:

Obtain the following materials:

ÿ  Burette

ÿ  Funnel

ÿ  Retort stand

ÿ  Burette clamp

ÿ  Pipette pump

ÿ  A 125-mL Erlenmeyer flask to hold vinegar for titration

ÿ  10-mL pipette for pipetting 10.00mL vinegar in a 125-mL Erlenmeyer flask

ÿ  0.1mol/L NaOH in a small beaker to fill the burette

ÿ  White piece of paper to be place under the Erlenmeyer flask

ÿ  Indicator (i.e. phenolphthalein)

ÿ  Wash bottle

ÿ  Goggles

III. Results:

What is the volume of vinegar in each titration? ______

Table 1: Volume data of 0.1M NaOH solution used to titrate vinegar solution in 3 trials

Trial # / 1 / 2 / 3 / Average Volume of NaOH (mL)
Final burette reading (final volume of titrant)
Initial burette reading (initial volume of titrant)
Volume of NaOH added (mL)

Analysis and Evaluation:

1.  Write the overall equation for this titration (include states, must be balanced).

2.  Write the net ionic equation for the reaction; i.e. show only those ions which actually take part in the reaction.

3.  What happened at the endpoint of the titration?

4. If the solution remaining in the Erlenmeyer flask after the titration were evaporated to dryness, what substance would be obtained?

5. Show your calculation to answer the question: what is the concentration of vinegar before the dilution? (mol/L) Steps must be full and complete.

6. How confident are you that your techniques and measurements resulted in good evidence?

7. What are some sources of errors that you think might have affected the accuracy of your titration?

8. Evaluate the prediction: Asummig the manufacture’s claim is accurate, its someone in the

cafeteria diluting the vinegar? Include an accuracy calculation (percent difference) in your

evaluation.