Q.Which is stronger reducing agent Cr²⁺ or Fe²⁺?

Step 1. A stronger reducing agent is one that is MORE readily oxidised, i.e. has a more negative reduction potential for the couple in question (equivalently, a stronger drive toward the OXIDISED side of the equilibrium).

Step 2. For chromium: E°(Cr³⁺/Cr²⁺) = -0.41 V -- a negative value, meaning Cr²⁺ is strongly driven to lose an electron and become the more stable Cr³⁺.

Step 3. For iron: E°(Fe³⁺/Fe²⁺) = +0.77 V -- a positive value, meaning the equilibrium instead favours Fe³⁺ being reduced TO Fe²⁺, i.e. Fe²⁺ is comparatively stable/resistant to further oxidation relative to chromium's case. …

Compare the M³⁺/M²⁺ standard reduction potentials for chromium and iron; the more negative value identifies the ion more re …

• Comparing the wrong couple (e.g. M²⁺/M instead of M³⁺/M²⁺), which would answer a different question (how easily the metal itself is oxid …