Question

10. What is the molarity of a MnO4- solution if 23.5 mL of this solution is required to react completely with 30.0 mL of 0.134 M Fe2 solution according to the equation 5Fe2 (aq) MnO4-(aq) 8H (aq) ---> 5Fe3 (aq) Mn2 (aq) 4H2O(l)

Answer 1

Answer:

The molarity of a MnO4- solution

= 0.0342 M

Explanation:

Equation of reaction:

5Fe2 (aq) MnO4-(aq) 8H (aq) ---> 5Fe3 (aq) Mn2 (aq) 4H2O(l)

This is an example of redox titration.

Using titration formula:

CAVA/CBVA = NA/NB

where CA is the molarity of Fe2+ = (0.134 M)

CB is the molarity of MnO4- = (?????)

VA is the volume of Fe2+ = (30mL)

VB is the volume of MnO4- =(23.5mL)

NA is the numeric coefficient of Fe2+ in the equation of reaction = ( 5 )

NB is the numeric coefficient of MnO4- in the equation of reaction =(1)

Substituting the values into the formula;

0.134×30/CB×23.5 = 5/1

Therefore CB = 0.134×30/23.5×5

= 0.0342 M