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A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution having a concentration of 0.2278 M, 100ml of which was used. The solution was then titrated with Zn dust which converted Fe 3 of the solution to Fe 2. The Fe 2 required 1000ml of 0.13M K2Cr2O3 solution. Find the %of FeO and Fe2O3 ?
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A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution ha...
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A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution ha...
Given:
- Concentration of KMnO4 solution = 0.2278 M
- Volume of KMnO4 solution used = 100 mL
- Concentration of K2Cr2O7 solution = 0.13 M
- Volume of K2Cr2O7 solution used = 1000 mL

Procedure:
1. Reaction between FeO and KMnO4
2. Reaction between Fe2O3 and KMnO4
3. Reaction between Fe2+ and K2Cr2O7

Step 1: Reaction between FeO and KMnO4
- FeO reacts with KMnO4 in an acidic medium to form Fe2+ and Mn2+ ions.
- The balanced equation for this reaction is:
5FeO + 2KMnO4 + 8H2SO4 → 5FeSO4 + K2SO4 + 2MnSO4 + 8H2O

Step 2: Reaction between Fe2O3 and KMnO4
- Fe2O3 reacts with KMnO4 in an acidic medium to form Fe2+ and Mn2+ ions.
- The balanced equation for this reaction is:
Fe2O3 + 4KMnO4 + 4H2SO4 → 2FeSO4 + 4K2SO4 + 4MnSO4 + 4H2O

Step 3: Reaction between Fe2+ and K2Cr2O7
- Fe2+ reacts with K2Cr2O7 in an acidic medium to form Fe3+ and Cr3+ ions.
- The balanced equation for this reaction is:
6FeSO4 + K2Cr2O7 + 7H2SO4 → 3Fe2(SO4)3 + Cr2(SO4)3 + K2SO4 + 7H2O

Calculations:
1. Calculate the moles of KMnO4 used:
Moles of KMnO4 = Concentration x Volume
= 0.2278 M x 0.1 L
= 0.02278 moles

2. Calculate the moles of K2Cr2O7 used:
Moles of K2Cr2O7 = Concentration x Volume
= 0.13 M x 1 L
= 0.13 moles

3. From the balanced equations, we can see that:
- 1 mole of FeO reacts with 2 moles of KMnO4
- 1 mole of Fe2O3 reacts with 4 moles of KMnO4
- 6 moles of FeSO4 react with 1 mole of K2Cr2O7

4. Calculate the moles of FeO and Fe2O3:
Let x be the moles of FeO
Let y be the moles of Fe2O3

From the above information, we can write the following equations:
5x + 2y = 0.02278 (from Step 1)
x + 2y = 0.02278/5
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Titrations are one of the methods we can use to discover the precise concentrations of solution. A typical titration involves adding a solution from a burette to another solution in a flask. The endpoint of the titration is found by watching a colour change taking place. However, a problem arises when a suitable indicator cannot be found, or when the colour changes involved are unclear. In cases redox potential may sometimes come to the rescue.A particularly well known example (Fig.1) is a method of discovering the concentration of iron in a solution by titrating them with a solution of cerium (IV). The redox potential that areof interest here are EFe3+/Fe2+ = + 0.77 V and ECe4+/Ce3+ = + 1.61 V. These tell us that cercium (IV) ions are the oxidizing agents, and iron (II) ions are the reducing agent. They should react according to the equationFe2+ (aq) + Ce4+ (aq) Fe3+ (aq) + Ce3+ (aq)Now imagine that we know the concentration of the cerium (IV) ions solution in the burette. We want to measure the concentration of the iron (II) solution. If we add just one drop of the cerium (IV) solution from the bruette, some of the iron (II) ions will be oxidised. As a consequence the beaker would now contain a large number of unreacted ions, but also some iron (III) ions as well. All of the cerium (III). The solution in the beaker now represents an iron(III)/iron(II) half cell, although not at standard conditions. Thus the e.m.f. of the cell will be near, but not equal, to EFe3+/Fe2+.to ad cerium (IV) solution, the number of iron (II) ions is gradually reduced and eventually only a very few are left (Tabl e).At this stage the next few drops of cerium (IV) solution convert all the remaining iron (II) ions into iron (III), and some of the cerium (IV) ions are left unreacted. Once this happens we no longer ions and a smaller number of cerium (IV) ions. The solution in the beaker now behaves as a cerium (IV)/cerium (III) half-cell (although not a standard one).Just before all the iron (II) ions are converted into iron (III) we have a cell with an e.m.f.of around + 0.77 V. After all the iron (II) ions are oxidised, we have a cell with an e.m.f. of about + 1.61 V. This rapid rise in e.m.f. occurs with the addition of hust one drop of cerium (IV) solution. You should be able to understand why a graph of cell e.m.f. against volume ofcerium (IV) solution added looks like that of Fig. 2. The end point of the titration can be read from the graph and the concentration of the iron (II) solution calculated in the usual wayQ.Imagine you were given a solution of potassium dichromate (VI) in a beaker, and a solution of iron (II) sulphate in a burette. You do not know the concentration of dichromate (VI) ions, but the concentration of the iron (II) solution is known. Your task is to carry out a redox titration using the two solutions in order to determine the concentration of dichromate(VI) ions. Sketch a graph how the e.m.f. changes in the course of above titration. E Cr2O2-7/Cr3+ = 1.33 V, EFe3+/Fe2+ = 0.77 V.

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A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution having a concentration of 0.2278 M, 100ml of which was used. The solution was then titrated with Zn dust which converted Fe 3 of the solution to Fe 2. The Fe 2 required 1000ml of 0.13M K2Cr2O3 solution. Find the %of FeO and Fe2O3 ?
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A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution having a concentration of 0.2278 M, 100ml of which was used. The solution was then titrated with Zn dust which converted Fe 3 of the solution to Fe 2. The Fe 2 required 1000ml of 0.13M K2Cr2O3 solution. Find the %of FeO and Fe2O3 ? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution having a concentration of 0.2278 M, 100ml of which was used. The solution was then titrated with Zn dust which converted Fe 3 of the solution to Fe 2. The Fe 2 required 1000ml of 0.13M K2Cr2O3 solution. Find the %of FeO and Fe2O3 ? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A mixture of FeO and Fe2O3 is reacted with acidified KMnO4 solution having a concentration of 0.2278 M, 100ml of which was used. The solution was then titrated with Zn dust which converted Fe 3 of the solution to Fe 2. The Fe 2 required 1000ml of 0.13M K2Cr2O3 solution. Find the %of FeO and Fe2O3 ?.
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