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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] straightforward thorough-understanding
Iron exposed to moist air develops a reddish-brown coating, while silver kept in air gradually turns black. (i) Name the chemical process responsible for each change and write the chemical formula of the product formed in each case. (ii) In what way are these two changes similar, and in what way are they different?
Generated by claude-sonnet-4-6 · 2026-06-26 00:55 · grounding rag
Model Answer

(i) Iron: Corrosion (rusting) — product is rust, $\text{Fe}_2\text{O}_3.\text{xH}_2\text{O}$. Silver: Corrosion (tarnishing) — product is silver sulphide, $\text{Ag}_2\text{S}$.
(ii) Similar: Both are corrosion — metals reacting with substances in air. Different: Iron reacts with oxygen and moisture; silver reacts with sulphur in air.

Source: Chapter 3, Section 3.5 Corrosion; Chapter 1, Section 1.3.1

Explanation

Even though this is marked as 1 mark, it has two parts — examiners expect both to be addressed briefly. Key points: use the word "corrosion" for both, give correct formulae ($\text{Fe}_2\text{O}_3.\text{xH}_2\text{O}$ and $\text{Ag}_2\text{S}$), and note that the difference lies in what the metal reacts with (oxygen + moisture vs. sulphur).

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