Unit 1 PPA 1

Question 1

What is the trioxalatoferrate(III) complex ion composed of?

Answer 1

Three oxalate ions bound to an iron(III) ion in an octahedral arrangement

Question 2

What colour is the Fe2+ ion

Answer 2

Pale green

Question 3

What is the light brown precipitate that forms?

Answer 3

Iron (II) oxalate

Question 4

What is the purpose of the hydrogen peroxide?

Answer 4

To oxidise the iron (II) ions to Iron(III) ions.

Question 5

What should 1 mole of hydrated ammonium iron (II) sulphate be converted to?

Answer 5

Hydrated potassium trixalatoferrate(III)

Question 6

Why might the percentage yield be less than 100%

Answer 6

Some side reactions may have taken place
There may have been impurities in the initial reactants
There may have been mass transfer losses
There are always losses during crystallisation since some of the product will remain in solution