ElectrochemistryhardNUMERICAL

A solution of Fe (SO ) is electrolyzed for ‘x' min with a current of 1.5 A to deposit 0.3482 g of FeElectrochemistry Chemistry Question

Question

A solution of Fe (SO ) is electrolyzed for ‘x' min with a current of 1.5 A to deposit 0.3482 g of Fe. The value of x is ___. [nearest integer] Given: 1 F = 96500 C mol Atomic mass of Fe = 56 g mol 2 4 3 –1 –1

Answer: 20

💡 Solution & Explanation

**Step 1: Identify the reduction reaction** Fe³⁺ gains 3 electrons to form Fe: Fe³⁺ + 3e⁻ → Fe **Step 2: Calculate moles of Fe deposited** Moles of Fe = mass/atomic mass = 0.3482/56 = 0.00622 mol **Step 3: Calculate total electrons required** From the equation, 1 mol Fe requires 3 mol electrons Electrons needed = 0.00622 × 3 = 0.01866 mol e⁻ **Step 4: Convert moles of electrons to charge (coulombs)** Charge (Q) = moles of e⁻ × Faraday constant Q = 0.01866 × 96500 = 1800.69 C **Step 5: Use the relationship between charge, current, and time** Q = I × t where Q = charge (C), I = current (A), t = time (s) 1800.69 = 1.5 × t t = 1800.69/1.5 = 1200.46 seconds **Step 6: Convert seconds to minutes** t = 1200.46/60 = 20.01 minutes ≈ 20 minutes Therefore, the answer is 20.

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