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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
Which of the following conditions is essential for iron to rust? (A) Presence of air alone (B) Presence of water alone (C) Presence of both air and water (D) Presence of carbon dioxide alone
  1. A Presence of air alone
  2. B Presence of water alone
  3. C Presence of both air and water
  4. D Presence of carbon dioxide alone
Generated by claude-sonnet-4-6 · 2026-06-26 01:04 · grounding rag
Model Answer

(C) Presence of both air and water

Iron rusts only when exposed to both air (oxygen) and water simultaneously, as shown in Activity 3.14 — nails in dry air or boiled water (without air) did not rust.

Source: Chapter 3, Section 3.5 Corrosion

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Explanation

The textbook Activity 3.14 clearly demonstrates that nails rust only in test tube A (air + water), not in B (water only, no air) or C (dry air, no water). Examiners expect you to select option C and may award a mark only for the correct option — no justification is needed in an MCQ, but knowing the reason helps if a follow-up short-answer appears.

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