Class 10 Science Chapter 1 MCQ Bilingual Test | Chemical Reactions and Equations Class 9 Science Matter in Our Surroundings Scientific Visual

Class 10 Science Chapter 1 MCQ Bilingual Test
(Chemical Reactions and Equations / रासायनिक अभिक्रियाएं एवं समीकरण)

NCERT / CBSE Class 10 Science Series

Published by: Air View Institute

Academic Mentor: Praveen Kumar Sahu

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Class 10 Science Chemical Reactions and Equations 3D Test Overview Graphic

Comprehensive Guide: Chapter 1 Chemical Reactions and Equations (रासायनिक अभिक्रियाएं एवं समीकरण)

Class 10 Science Chapter 1 "Chemical Reactions and Equations" (रासायनिक अभिक्रियाएं एवं समीकरण) lays the groundwork for basic physical chemistry. Understanding how chemical bonds break and reform, balancing equations according to conservation of mass, and classifying chemical transformations are fundamental skills for CBSE Board examinations. This detailed bilingual guide and 50-question practice portal created by Air View Institute guarantees total conceptual clarity.

1. Chemical Equations & Balancing (रासायनिक समीकरण और संतुलन)

A chemical reaction occurs when one or more substances undergo a transformation to yield new chemical products with distinct properties. A word equation represents this symbolically using chemical formulas.

Law of Conservation of Mass (द्रव्यमान संरक्षण का नियम): Matter can neither be created nor destroyed in a chemical reaction. Therefore, the total mass of reactants must equal the total mass of products. Balancing a skeletal chemical equation ensures that the number of atoms for each element remains equal on both sides.

Example: Burning magnesium ribbon in oxygen:
2Mg(s) + O₂(g) → 2MgO(s) + Heat

📌 Essential Study Links & Resources

2. Types of Chemical Reactions (रासायनिक अभिक्रियाओं के प्रकार)

Chemical reactions are broadly categorized based on molecular rearranging mechanisms:

Combination Reaction (संयोजन अभिक्रिया): Two or more reactants combine to form a single product. E.g., Quicklime reacting with water: CaO(s) + H₂O(l) → Ca(OH)₂(aq) + Heat.
Decomposition Reaction (वियोजन या अपघटन अभिक्रिया): A single reactant breaks down into two or more simpler products using Heat (Thermal), Light (Photolytic), or Electricity (Electrolytic). E.g., Heating Ferrous Sulphate: 2FeSO₄(s) → Fe₂O₃(s) + SO₂(g) + SO₃(g).
Displacement Reaction (विस्थापन अभिक्रिया): A more reactive element displaces a less reactive element from its salt solution. E.g., Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s).
Double Displacement Reaction (द्विविस्थापन अभिक्रिया): Exchange of ions between two aqueous reactants forming an insoluble precipitate. E.g., Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s)↓ + 2NaCl(aq).
Redox Reactions / Oxidation & Reduction (उपचयन एवं अपचयन): Oxidation is gain of oxygen or loss of hydrogen. Reduction is loss of oxygen or gain of hydrogen. Both occur simultaneously in Oxidation-Reduction (Redox) reactions. E.g., CuO + H₂ → Cu + H₂O.

3. Real-World Redox Effects: Corrosion & Rancidity (संक्षारण और विकृतगंधिता)

Corrosion (संक्षारण): The gradual degradation of metals when exposed to atmospheric oxygen, moisture, and acids. Iron rusts to form reddish-brown hydrated iron oxide (Fe₂O₃·xH₂O), silver tarnishes black due to silver sulphide (Ag₂S), and copper develops a green coat of basic copper carbonate.

Rancidity (विकृतगंधिता): Oxidation of fats and oils in food substances leads to unpleasant smells and bad taste. Methods to prevent rancidity include flushing chips packets with inert Nitrogen gas, storing food in airtight containers, and adding antioxidants (BHA/BHT).