A dilute solution of sulphuric acid is electrolysed using a current of 0.10 A for 2 hours to produce — Electrochemistry Chemistry Question

💡 Solution & Explanation

**Step 1: Calculate total charge passed** Charge (Q) = Current × Time Q = 0.10 A × (2 × 3600 s) = 0.10 × 7200 = 720 C **Step 2: Calculate total moles of electrons** Using Faraday's law: Moles of electrons = Q/F = 720/96500 = 0.00746 mol **Step 3: Write the electrolysis equations** At cathode: 2H⁺ + 2e⁻ → H₂ At anode: 2H₂O → O₂ + 4H⁺ + 4e⁻ **Step 4: Calculate moles of gases produced** From the equations: - 2 moles of e⁻ produce 1 mole of H₂ - 4 moles of e⁻ produce 1 mole of O₂ Moles of H₂ = 0.00746/2 = 0.00373 mol Moles of O₂ = 0.00746/4 = 0.00187 mol Total moles of gas = 0.00373 + 0.00187 = 0.00560 mol **Step 5: Calculate total volume at STP** Volume = moles × molar volume Volume = 0.00560 mol × 22.7 L/mol = 0.127 L = 127 cm³ Therefore, the answer is 127.