EᶱCr₂O₇^2-/Cr³⁺ = 1.33V

EᶱMnO₄^–/Mn²⁺ = 1.51V

EᶱCl₂/Cl^– = 1.36V

EᶱCr³⁺/Cr = -0.74V

(i) Cl–

(ii) Cr

(iii) Cr3+

(iv) Mn

Correct Answer: (ii) Cr

Explanation:  The most powerful reducing agent is easily oxidized, that is, with the greatest oxidation potential. Thus, Cr is the strongest reducing agent.