• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Preparation of Potassium Trioxalatoferrate (III)

Extracts from this document...


Preparation of Potassium Trioxalatoferrate (III) Introduction The aim of this experiment was to calculate the percentage yield in the preparation of crystals of potassium trioxalatoferrate (III). This contains the complex ion trioxalatoferrate which is made up of three oxalate ions (C2O42-) bonded to an iron (III) ion in an octahedral shape: 3- C2O4 C2O4 Fe C2O4 Trioxalatoferrate (III) Ion In this complex ion, the oxalate ions act as ligands. They act as ligands because each one of the negative oxalate ions donates 2 pairs of electrons in its bond to the iron ion making the oxalate ions chelating bidentate ligands. The preparation of potassium trioxalatoferrate (III) takes place in three stages. Firstly, ammonium iron (II) sulphate reacts with oxalic acid to give iron (II) oxalate and ammonium hydrogensulphate: (NH4)2Fe(SO4)2 (aq) + H2C2O4 (aq) --> FeC2O4 (s) + 2NH4HSO4 (aq) Then the iron (II) oxalate is reacted with hydrogen peroxide and potassium oxalate, producing potassium trioxalatoferrate (III) and iron (III) hydroxide: 6FeC2O4 (s) + 6K2C2O4 (aq) + 3H2O2 (aq) ...read more.


The liquid was decanted off and 50cm3 of hot deionised water was added to the precipitate. The mixture was stirred. After the precipitate had settled, the liquid was once again decanted off. 10cm3 of potassium oxalate solution was added to the washed precipitate and the mixture was heated to about 40oC. 20cm3 of "20 volume" hydrogen peroxide solution was added slowly with continuous stirring to the mixture. The temperature was kept close to 40oC during the addition of the hydrogen peroxide. This changed the colour from orange to dark red / brown. The mixture was heated nearly to boiling and oxalic acid solution was added, dropwise with stirring, until the brown precipitate of iron (III) hydroxide dissolved. The solution changed in colour from dark red / brown to clear lime green. The reaction mixture was kept near to boiling during the addition of the oxalic acid. The hot solution was filtered through a fluted filter paper into a crystallising basin. ...read more.


This results in possible errors in the balance and measuring cylinder, meaning the mass of hydrated ammonium iron (II) sulphate and the volume of oxalic acid, potassium oxalate, hydrogen peroxide, deionised water and ethanol could all be slightly wrong. If less of each compound was put in, the mass of potassium trioxalatoferrate (III) would not be as much as anticipated. There are more factors that result in the yield being less than 100%, including systematic errors. These include flaws in the equipment, flaws in the procedure (such as when the solution is transferred from the beaker to the crystallising basin some solution remains in the beaker) and lack of purity in reagents if they are not as concentrated as stated because some of it has reacted with air over a long period of time. Human error is also a major contributor to the yield not being 100%. In the preparation of potassium trioxalatoferrate, the hydrogen peroxide acts as the oxidising agent. ?? ?? ?? ?? 1 Lee McFadzean ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. How much Iron (II) in 100 grams of Spinach Oleracea?

    I tried using hot water from a kettle to dissolve the solute in and this worked well, enabling me to get the concentration of solution that I wanted. But when I put this concentration of Potassium Manganate (aq) into the burette I found that it covered the walls in a

  2. Determining the purity of Iron Wool.

    Using a pipette 25cm3 of stock sodium carbonate solution should be transferred into a clean conical flask and the burette filled with 0.209M hydrochloric acid. Add 3-4 drops of methyl orange indicator to the base solution and swirls (colour should be yellowish).

  1. In this experiment you will prepare a complex compound of iron, potassium trioxalatoferrate(III), K3Fe(C2O4)3. ...

    Decant the supernatant liquid and wash the ppt by stirring it with 50 cm3 of hot water (~80oC).

  2. The aim of this assignment is to produce 1-bromobutane in the laboratory and write ...

    (A high temperature may vaporise quickly the Butan-1-ol, which will decrease the yield. After the reaction, we removed the top funnel and distillation head from the top of the flask and the cooling bath from around the flask and dried the outside of the flask.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work