Oxidation Reduction Titrations

Step 1: Write the balanced redox reaction in neutral/alkaline medium.

2MnO_4%5E-%20%2B%20I%5E-%20%2B%20H_2O%20%5Crightarrow%202MnO_2%20%2B%20IO_3%5E-%20%2B%202OH%5E-

Step 2: Determine the stoichiometry.
2 moles of

MnO_4%5E-

react with 1 mole of

I%5E-

.
Step 3: Calculate moles of KI.
Moles of

KI%20%3D%20%5Ctext%7BMolarity%7D%20%5Ctimes%20%5Ctext%7BVolume%7D%20%3D%200.5%20%5C%2C%20M%20%5Ctimes%201%20%5C%2C%20L%20%3D%200.5%20%5C%2C%20mol

. This means moles of

I%5E-%20%3D%200.5%20%5C%2C%20mol

.
Step 4: Calculate moles of $KMnO_4$ required.
From stoichiometry, moles of

KMnO_4%20%3D%202%20%5Ctimes%20%5Ctext%7Bmoles%20of%20%7D%20I%5E-%20%3D%202%20%5Ctimes%200.5%20%5C%2C%20mol%20%3D%201%20%5C%2C%20mol

.
Step 5: Calculate the volume of $KMnO_4$ solution.
Volume of

KMnO_4%20%3D%20%5Cfrac%7B%5Ctext%7Bmoles%20of%20%7D%20KMnO_4%7D%7B%5Ctext%7BMolarity%20of%20%7D%20KMnO_4%7D%20%3D%20%5Cfrac%7B1%20%5C%2C%20mol%7D%7B0.02%20%5C%2C%20M%7D%20%3D%2050%20%5C%2C%20L

.
Thus, the volume of 0.02M

KMnO_4

required is

%5Cboxed%7B50%7D%20%5C%2C%20L

Chapter Questions
2 MCQs