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Arrange the following redox couples in the increasing order of their reducing strength: array ll [ A ]= Cu / Cu ²⁺ & E ^0=-0.34 ~V [ ~B ]= Ag / Ag ⁺ & E ^0=-0.8 ~V [ C ]= Ca / Ca ²⁺ & E ^0=+2.87 ~V [ D ]= Cr / Cr ³⁺ & E ^0=+0.74 ~V array

Options

  1. AB < A < D < C
  2. BD < A < C < B
  3. CA < C < B < D
  4. DC < D < A < B

Correct answer

A. B < A < D < C

Step-by-step solution

The reducing strength of a species is determined by its standard oxidation potential. A higher standard oxidation potential ( E⁰_ ox ) indicates a stronger reducing agent. The given values are standard oxidation potentials ( E⁰_ ox ) for the couples M/M^ n+ . The values are: A: Cu/Cu²⁺ , E⁰_ ox = -0.34 V B: Ag/Ag⁺ , E⁰_ ox = -0.8 V C: Ca/Ca²⁺ , E⁰_ ox = +2.87 V D: Cr/Cr³⁺ , E⁰_ ox = +0.74 V Comparing the values: -0.8 This corresponds to the order: B Thus, the increasing order of reducing strength is B Answer: B < A

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