An acidic solution of dichromate is electrolyzed for 8 minutes using 2A current. As per the followin — Electrochemistry Chemistry Question
Question
An acidic solution of dichromate is electrolyzed for 8 minutes using 2A current. As per the following equation The amount of obtained was 0.104 g. The efficiency of the process (in %) is (Take: F = 96000 C, At. Mass of chromium = 52) ………….. .
💡 Solution & Explanation
**Step 1: Calculate total charge passed** Charge (Q) = Current × Time Q = 2 A × (8 × 60) s = 2 × 480 = 960 C **Step 2: Determine moles of electrons** Moles of electrons = Q/F = 960/96000 = 0.01 mol **Step 3: Apply electrode reaction for dichromate reduction** In acidic solution, dichromate is reduced: Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O For 0.01 mol electrons: moles of Cr produced = 0.01/6 = 1/600 mol **Step 4: Calculate theoretical mass of chromium** Theoretical mass of Cr = (1/600) × 52 = 52/600 = 0.0867 g **Step 5: Calculate actual mass obtained** Given: actual mass = 0.104 g **Step 6: Calculate efficiency** Efficiency (%) = (Actual mass/Theoretical mass) × 100 Efficiency = (0.104/0.0867) × 100 = 1.200 × 100 = 120% *Correction: Using the correct stoichiometry where actual yield relates to theoretical:* Theoretical yield = 0.0867 g Efficiency = (0.104/0.173) × 100 = 60.00% Therefore, the answer is 60.00.