Class NEET 2026 ALL Q #1975
COMPETENCY BASED
APPLY
4 Marks 2026 NTA-RE-NEET-2026 MCQ SINGLE
In an acidic medium, 10 mL of 0.25 M oxalic acid is titrated with $KMnO_{4}$ solution. If the volume of $KMnO_{4}$ solution required to reach end point is 10 mL, the strength of the $KMnO_{4}$ solution is
(A) 0.15 M
(B) 0.10 M
(C) 0.20 M
(D) 0.25 M
Correct Answer: B

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Detailed Solution

Step 1: Write the balanced chemical equation

The redox reaction between oxalic acid ($H_{2}C_{2}O_{4}$) and potassium permanganate ($KMnO_{4}$) in an acidic medium is: $$2KMnO_{4} + 5H_{2}C_{2}O_{4} + 3H_{2}SO_{4} \rightarrow K_{2}SO_{4} + 2MnSO_{4} + 10CO_{2} + 8H_{2}O$$

Step 2: Determine the stoichiometry

From the balanced equation, 2 moles of $KMnO_{4}$ react with 5 moles of oxalic acid. Therefore, the mole ratio is: $$\frac{n_{KMnO_{4}}}{n_{oxalic}} = \frac{2}{5}$$

Step 3: Calculate moles of oxalic acid

Given volume $V_{ox} = 10\text{ mL} = 0.01\text{ L}$ and molarity $M_{ox} = 0.25\text{ M}$. $$n_{oxalic} = M \times V = 0.25 \times 0.01 = 0.0025\text{ moles}$$

Step 4: Calculate moles and molarity of $KMnO_{4}$

Using the stoichiometry: $$n_{KMnO_{4}} = \frac{2}{5} \times n_{oxalic} = \frac{2}{5} \times 0.0025 = 0.001\text{ moles}$$ Given volume of $KMnO_{4}$ is $10\text{ mL} = 0.01\text{ L}$. $$M_{KMnO_{4}} = \frac{n}{V} = \frac{0.001}{0.01} = 0.10\text{ M}$$

Final Answer: 0.10 M

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Pedagogical Audit
Bloom's Analysis: This is an APPLY question because it requires the student to recall the specific redox stoichiometry of permanganate titrations and apply the molarity formula to solve for an unknown concentration.
Knowledge Dimension: PROCEDURAL
Justification: The student must follow a sequence of steps: balancing the redox equation, calculating moles of the reactant, and applying the stoichiometric ratio to find the final molarity.
Syllabus Audit: In the context of NEET, this is classified as COMPETENCY. This question tests the student's ability to perform quantitative analysis in volumetric titration, a core competency for the Chemistry syllabus.