Corrosion MCQs Quiz | Class 10
This quiz is designed for Class X students for the subject Science (Code 086), covering Unit I: Chemical Substances – Nature and Behaviour. The specific topic is Corrosion, focusing on its meaning and using rusting as a primary example. Solve these 10 multiple-choice questions to test your understanding, check your score, and download the detailed solution PDF for revision.
Overview of Corrosion
Corrosion is a natural process where a refined metal is converted into a more chemically stable form, such as oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. In Class 10 Science, Unit I, we focus primarily on the corrosion of iron, known as rusting, and briefly look at other metals like silver and copper.
Key Concepts
- Rusting of Iron: When iron is exposed to moist air for a long time, it acquires a coating of a brown flaky substance called rust. Chemically, rust is hydrated iron(III) oxide.
- Conditions for Rusting: Both air (oxygen) and moisture (water) are essential for rusting to occur. If either is missing, rusting does not happen.
- Corrosion of Copper: Copper reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface to gain a green coat. This green substance is basic copper carbonate.
- Corrosion of Silver: Silver articles become black after some time when exposed to air because they react with sulfur in the air to form a coating of silver sulfide.
- Prevention: Rusting can be prevented by painting, oiling, greasing, galvanization (coating with zinc), chrome plating, anodizing, or making alloys.
Comparison of Corroded Metals
| Metal | Corrosion Product | Color of Coating |
|---|---|---|
| Iron | Hydrated Iron(III) Oxide | Reddish-Brown |
| Copper | Basic Copper Carbonate | Green |
| Silver | Silver Sulfide | Black |
Quick Revision Notes
- Definition: The eating away of metals by the action of air, moisture, or a chemical on their surface.
- Gold and Platinum: These are noble metals and do not corrode easily.
- Aluminium: Forms a protective oxide layer that prevents further corrosion (anodizing improves this).
- Galvanization: A method of protecting steel and iron from rusting by coating them with a thin layer of zinc.
Extra Practice Questions
- Why do silver anklets turn black after some time?
- Write the chemical formula of rust.
- Name two methods to prevent the rusting of iron.
- What is the green coating formed on copper vessels?
- Does iron rust in distilled water boiled to remove air?
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