An electrolytic cell is constructed for preparing hydrogen. For an average current of 2 ampere in the circuit, the time required to produce 450 mL of hydrogen at NTP is approximately

Step-by-step solution

22400 mL H 2 at STP = 1 mol H 2 So 450 ml H 2 at STP = 450 mL 22400 mL ×1 mol H 2 = 0.02 mol Electrode reaction 2 H + + 2 e - 2 F → H 2 1 m o l The liberation of 1 mol H 2 requires = 2 × 96500 C So the liberation of 0 .02 mol H 2 requires = 2 × 96500 × 0.02 C = 3860 C Time required to produce 0 .02 mol H 2 , t = Q i = 3860 2A = 1930 s ≃ 0 .503 hour ≈ 0.5 hour