The Question is from neet-chemistry d-f-block-elements , and it was created by the author THIRUPATHI REDDY

Question

A mixture of $FeSO_4$ and $Fe_2(SO_4)_3$ is titrated with acidified $KMnO_4$ solution.  The milliequivalents of $KMnO_4$ required are equal to:

THIRUPATHI REDDY · Accepted Answer

## CORE INFORMATION
✓ **Answer**: A
## CONCEPT FRAMEWORK
 **Primary Concept**: Redox titration and equivalent weight calculations
 **Related Topics**: Oxidation states, stoichiometry, permanganometry
 **Prerequisites**: Understanding of redox reactions, balancing redox reactions, and the concept of milliequivalents.
## SOLUTION PATHWAY
**Given Information**:
A mixture of $FeSO_4$ and $Fe_2(SO_4)_3$ is titrated with acidified $KMnO_4$.
**Method & Steps**:
1. **Identify the redox reactions:**
   In acidic medium, $MnO_4^-$ is reduced to $Mn^{2+}$ and $Fe^{2+}$ is oxidized to $Fe^{3+}$:
   $MnO_4^- + 8H^+ + 5e^- ightarrow Mn^{2+} + 4H_2O$ (Reduction half-reaction)
   $Fe^{2+} ightarrow Fe^{3+} + e^-$ (Oxidation half-reaction)
   $Fe_2(SO_4)_3$ does not participate in the redox reaction as iron is already in its +3 oxidation state.
2. **Determine the n-factor:**
   The n-factor (number of electrons transferred) for $KMnO_4$ is 5 (from the reduction half-reaction).
   The n-factor for $FeSO_4$ is 1 (from the oxidation half-reaction).
3. **Relate milliequivalents:**
   Milliequivalents (meq) = Normality × Volume (mL)
   In a redox titration, meq of oxidant = meq of reductant.
   Therefore, meq of $KMnO_4$ = meq of $Fe^{2+}$
4. **Conclusion:**
   The milliequivalents of $KMnO_4$ required are equal to the milliequivalents of $Fe^{2+}$ only.  $Fe^{3+}$ does not react with $KMnO_4$ under these conditions.
## OPTION ANALYSIS
[A] ✓: Milliequivalents of $Fe^{2+}$ only: Correct. Only $Fe^{2+}$ undergoes oxidation and reacts with $KMnO_4$.
[B] :x: Milliequivalents of $Fe^{3+}$ only: Incorrect. $Fe^{3+}$ is already in its highest oxidation state and does not react with $KMnO_4$.
[C] :x: Milliequivalents of both $Fe^{2+}$ and $Fe^{3+}$: Incorrect. Only $Fe^{2+}$ reacts with $KMnO_4$.
[D] :x: Twice the milliequivalents of $Fe^{2+}$: Incorrect. The stoichiometry of the reaction shows a 1:1 relationship between $KMnO_4$ and $Fe^{2+}$.
## LEARNING AIDS
 **Common Mistakes**:
  1. Ignoring the oxidation states of iron:  Failing to recognize that only $Fe^{2+}$ is involved in the redox reaction leads to incorrect calculations.
  2. Incorrect n-factor calculation:  An incorrect n-factor for either $KMnO_4$ or $Fe^{2+}$ will lead to an incorrect answer.
 **Quick Tips**:
  1. Always balance the redox reaction to determine the n-factor.
  2. Remember that milliequivalents of oxidant = milliequivalents of reductant in a redox titration.

THIRUPATHI REDDY · Answer

The correct Option is "Milliequivalents of $Fe^{2+}$ only"

THIRUPATHI REDDY · Answer

Milliequivalents of $Fe^{3+}$ only

THIRUPATHI REDDY · Answer

Milliequivalents of both $Fe^{2+}$ and $Fe^{3+}$

THIRUPATHI REDDY · Answer

Twice the milliequivalents of $Fe^{2+}$

NEET Chemistry d- and f-Block Elements MCQs

Select Topic

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

NEET Subjects

Our Bots

Company