Redox Titrations

Question 1

Why are indicators not always needed for redox titrations?

Answer 1

Because one chemical is a transition metal which are coloured. A change in its colour or fading of the colour indicates the end point

Question 2

What are the examples of redox tritrations you need to know?

Answer 2

Manganate (VII), Ethanedioate and dichromate (VI)

Question 3

Describe the procedure of Manganate (VII) Tritration.

Answer 3

1. Standard solution of KMnO4 added to burette
2. Using a pipette, a measured volume of solution under analysis transferred to conical flask
3. Excess dilute H2SO4 added to provide H+
4. Trial titration carried out
5. KMnO4 added from burette and oxidises solution under analysis (Fe2+ —> Fe3+
6. MnO4- ions reduced to Mn2+ and lose purple colour (pale pink)
7. Once all the chemical under analysis has been oxidised, next drop of KMnO4 remains purple after swirling. pale pink —> purple
8. Record Titre
9. Repeat titration until 2 concordant (withing 0.1cm3) results are achieved

Question 4

What is the equation of redox tritration of permanganate and Fe2+?

Answer 4

MnO4- + 5Fe2+ + 8H+ —> 5Fe3+ + Mn 2+ + 4H2O