When ferrous oxalate is titrated against K₂Cr₂O₇ m eq. of Fe²⁺, C₂O₄²⁻ and Cr₂O₇²⁻ in the redox reaction are X, Y and Z respectively, then:

• (A) X = Y
• (B) X + Y = Z
• (C) X + 2Y = Z
• (D) 2X + 6Y + 6Z

In the titration of ferrous oxalate (FeC₂O₄) against potassium dichromate (K₂Cr₂O₇), a redox reaction occurs where Fe²⁺ is oxidized and Cr₂O₇²⁻ is reduced. To analyze the equivalents involved, we can define:

• X: m equivalents of Fe²⁺
• Y: m equivalents of C₂O₄²⁻
• Z: m equivalents of Cr₂O₇²⁻

In this reaction, one mole of Cr₂O₇²⁻ reacts with six moles of electrons, while ferrous ions (Fe²⁺) and oxalate ions (C₂O₄²⁻) participate in the reaction as well. The stoichiometry of the reaction shows that:

X + 2Y = Z

This means that for every mole of Cr₂O₇²⁻, two moles of oxalate ions are consumed, while one mole of Fe²⁺ is oxidized. Therefore, the correct relationship among the equivalents is:

Answer: (C) X + 2Y = Z