JEE Main 2026 Chemistry question
The mass of iron converted into Fe₃O₄ by the action of 18 g of steam is: (Given: Molar mass of H, O and Fe are 1, 16 and 56 g mol⁻¹ respectively) Assume iron is present in excess:
Answer: (D)
Solution
3Fe + 4H₂O → Fe₃O₄ + 4H₂. 18 g H₂O = 1 mol, which needs 3/4 mol Fe = 0.75 × 56 = 42 g.