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Match List I with List II. List I (Reagent) List II (Classification and Property) (A) NaOH (I) Primary standard for redox titrations (B) K₂Cr₂O₇ (II) Secondary standard because it is deliquescent and absorbs CO ₂ (C) KMnO ₄ (III) Primary standard for acid-base titrations (D) Na₂CO₃ (IV) Secondary standard because it is unstable in aqueous solution and affected by light Choose the correct answer from the options given

Options

  1. A(A)-(II), (B)-(IV), (C)-(I), (D)-(III)
  2. B(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  3. C(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
  4. D(A)-(IV), (B)-(I), (C)-(II), (D)-(III)

Correct answer

C. (A)-(II), (B)-(I), (C)-(IV), (D)-(III)

Step-by-step solution

(A) NaOH is a secondary standard because it is deliquescent and readily absorbs moisture and CO ₂ from the atmosphere. (A) (II) (B) K₂Cr₂O₇ is available in high purity, is stable in air, and is used as a primary standard in redox titrations. (B) (I) (C) KMnO ₄ is a secondary standard because its aqueous solutions are unstable, decompose in the presence of light, and it is difficult to obtain perfectly pure. (C) (IV) (D) Na₂CO₃ can be obtained in highly pure, anhydrous form and is used as a primary standard for acid

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