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NEET 2026
Exam
NEET
Year
2026
Subject
Chemistry
Chapter
Chapter

NEET 2026 · Chemistry · Chapter

Consider the following redox reaction in an acidic medium: x MnO_4^...

Consider the following redox reaction in an acidic medium:

xMnO4−+yC2O42−+zH+→xMn2++2yCO2+z2H2Ox \text{MnO}_4^{-} + y \text{C}_2\text{O}_4^{2-} + z \text{H}^{+} \rightarrow x \text{Mn}^{2+} + 2y \text{CO}_2 + \dfrac{z}{2} \text{H}_2\text{O}

When the equation is correctly balanced using the smallest possible whole numbers, the values of the stoichiometric coefficients xx, yy, and zz are respectively:

Options

  1. A5,2,165, 2, 16
  2. B2,5,82, 5, 8
  3. C2,5,162, 5, 16
  4. D5,2,85, 2, 8

Correct answer

C. 2,5,162, 5, 16

Step-by-step solution

The given redox reaction can be split into two half-reactions.

Oxidation half-reaction:
C2O42−→2CO2+2e−\text{C}_2\text{O}_4^{2-} \rightarrow 2\text{CO}_2 + 2e^{-}

Reduction half-reaction:
MnO4−+8H++5e−→Mn2++4H2O\text{MnO}_4^{-} + 8\text{H}^{+} + 5e^{-} \rightarrow \text{Mn}^{2+} + 4\text{H}_2\text{O}

To balance the number of electrons, multiply the oxidation half-reaction by 55 and the reduction half-reaction by 22:

5C2O42−→10CO2+10e−5\text{C}_2\text{O}_4^{2-} \rightarrow 10\text{CO}_2 + 10e^{-}
2MnO4−+16H++10e−→2Mn2++8H2O2\text{MnO}_4^{-} + 16\text{H}^{+} + 10e^{-} \rightarrow 2\text{Mn}^{2+} + 8\text{H}_2\text{O}

Adding the two balanced half-reactions gives the overall balanced equation:

2MnO4−+5C2O42−+16H+→2Mn2++10CO2+8H2O2\text{MnO}_4^{-} + 5\text{C}_2\text{O}_4^{2-} + 16\text{H}^{+} \rightarrow 2\text{Mn}^{2+} + 10\text{CO}_2 + 8\text{H}_2\text{O}

Comparing this with the given equation xMnO4−+yC2O42−+zH+→xMn2++2yCO2+z2H2Ox \text{MnO}_4^{-} + y \text{C}_2\text{O}_4^{2-} + z \text{H}^{+} \rightarrow x \text{Mn}^{2+} + 2y \text{CO}_2 + \dfrac{z}{2} \text{H}_2\text{O}, we get:
x=2x = 2
y=5y = 5
z=16z = 16

Answer: 2,5,162, 5, 16
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