Developing Metals-1: Redox Titrations

Question 1

What metal in particular are Redox titrations used to find in samples

Answer 1

Iron (Fe2+)

Question 2

In Redox titration used to find the amount of iron in a sample what happens ( in terms of iron ions)

Answer 2

Fe2+ is oxidised to Fe3+ by an oxidising agent

Fe2+ —> Fe3+ + e-

Question 3

Name 2 oxidising agents used in iron redjx titrations

Answer 3

1. ACIDIFIED potassium manganate ( KMnO4)

2. ACIDIFIED potassium dichromate ( K2 Cr7 O7)

Question 4

What is a suitable acid for both oxiding agents

Answer 4

Both = DILUTE ( conc would oxidise some of Fe2+) sulphuric acid

Potassium dichromate = dilute HCl aswell ( potassium managate cannot use this as HCl is oxidised by MnO4- to form Cl2)

Question 5

Reacting (mole) ratio of iron ions and potassium managanage ions

Answer 5

Fe2+ : MnO4- = 5:1

Question 6

Reacting (mole) ratio of iron ions and potassium dichromate ions

Answer 6

Fe2+ : Cr2 O7 2- = 6:1

Question 7

Colour change at end point for potassium manganate

Answer 7

???

Question 8

Colour change at end point for potassium dichromate ( using indicator - name it)

Answer 8

????