What is the equivalent mass of potassium dichromate ( ) when it acts as an oxidizing agent in a stro — Redox Reactions and Volumetric Analysis Chemistry Question
Question
What is the equivalent mass of potassium dichromate ( $K_2Cr_2O_7$ ) when it acts as an oxidizing agent in a strongly acidic medium, assuming its molar mass is identically $M$ ?
💡 Solution & Explanation
The relevant reduction half-reaction for the potassium dichromate ion in an acidic medium is mathematically $Cr_2O_7^{2-} + 14H^+ + 6e^- \to 2Cr^{3+} + 7H_2O$ . The oxidation state of Chromium drops from $+6$ to $+3$ , representing a difference of $3$ electrons per atom. Since there are inherently two Cr atoms embedded in one single dichromate unit, the total number of electrons gained per molecule is $2 \times 3 = 6$ . The definitive n-factor is 6, making the equivalent mass $M/6$ .