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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] medium exam-ready
What is the correct balanced form of the skeletal equation: Fe + H₂O → Fe₃O₄ + H₂ ? (A) Fe + 4H₂O → Fe₃O₄ + 4H₂ (B) 3Fe + 4H₂O → Fe₃O₄ + 4H₂ (C) 3Fe + 3H₂O → Fe₃O₄ + 3H₂ (D) 2Fe + 4H₂O → Fe₃O₄ + 4H₂
  1. A Fe + 4H₂O → Fe₃O₄ + 4H₂
  2. B 3Fe + 4H₂O → Fe₃O₄ + 4H₂
  3. C 3Fe + 3H₂O → Fe₃O₄ + 3H₂
  4. D 2Fe + 4H₂O → Fe₃O₄ + 4H₂
Generated by claude-sonnet-4-6 · 2026-06-26 00:53 · grounding rag
Model Answer

(B) 3Fe + 4H₂O → Fe₃O₄ + 4H₂

Explanation

Balancing by hit-and-trial: oxygen needs coefficient 4 on H₂O (to match 4 O in Fe₃O₄), giving 8 H atoms, so 4H₂ on RHS. Then Fe must be 3 on LHS to match Fe₃O₄. All atoms balance: Fe=3, H=8, O=4 on both sides. Source: Chapter 1, Section 1.1.2.

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.