Oxidation-Reduction (Redox)
Titration of Oxalate in
K3Fe(C2O4)3·3H2O
First things first…

Safety:
Put bags away
 Goggles
 Lab Jacket
 Gloves
 Acidic Reactants!

Quiz!
 LAB!

What is titration anyway?
Using a buret, you can deliver a specific
volume of a solution for a reaction
 To read a volume in a buret, look at the
bottom of the meniscus

Be sure to note the start
volume and the final
volume.
 No bubble in tip!

Procedure
WEAR GLOVES! Permanganate will stain

Weigh 0.1g of the potassium trioxalatoferrate
into 3 separate 125 or 250 mL Erlenmeyers

Make sure to record mass to 0.00Xg
(3 significant figures)
Add ~20 mL of 1.0 M Sulfuric acid
 Rinse buret with two 5 mL portions KMnO4,
and then fill halfway with (X.XX M) KMnO4
 Titration!
Repeat for a total of 3 titrations

Actual Titration






Place the Erlenmeyer on a hot plate and stir until it
dissolves and temp 80-90ºC
Titrate KMnO4 from the buret, temp >60ºC
Keep stirring
As the endpoint approaches, titrate SLOWLY,
drop-wise until the sol’n becomes pink (reaches
end-point)
Waste: KMnO4 in buret goes to beaker back hood
Titrated solution goes down the sink
Calculations
2


5C2O4  2MnO4  16 H  2Mn
Moles KMnO4
reduced
2
 10CO2  8H 2O
VolKMnO4 ( L) MolarityKM nO4 (mol )

 XmolesKMnO
1
( L)
2
Moles C2O4
oxidized
Mass C2O4
XmolesKMnO4 5molC2O4
2

 YmolC 2O4
1
2molKMnO4
YmolC 2O4
1
2
88.02 gC2O4
MW
2 C2O

 ZgC2O4
2
1molC2O4
4
2
Weight %
2
ZgC2O4
100%  weight %
__ gCordComp
Sample mass
originally weighed (~0.1xxg)
Everything due before
leaving lab


Turn in today: pre-lab with calculations (yellow
sheet)
Finish calculations, including % error


Include pages from lab manual if yellow pages are not
easy to read
Enter data into computer/spreadsheet




Do initial log in
Password: last 3 digits g number
Then one individual member adds data
Group members: group id is the individual id who
entered data
Due Next Class
Freezing point depression quiz and pre-lab
 Lab Report:

Data analysis (based upon lab handout “Redox
Titration of Oxalate” on chem.gmu.edu/results
site)
 1-2 page double spaced discussion/conclusion
page
 Do not use discussion ?s
