In a fuel cell, 0.56 L of O₂ gas (STP) is consumed at the cathode. How many grams of H₂O (molar mass 18 g/mol) are produ
Cathode: O₂ + 4H⁺ + 4e⁻ → 2H₂O . Moles O₂ = (0.56/22.4) = 0.025 mol , Moles H₂O = 0.025 × 2 = 0.05 mol . Mass = 0.05 × 18 = 0.9 g .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Batteries - Primary Secondary and Fuel Cells
