Welcome To My School Study
Practice Class 10 Science Chapter 1 Chemical Reactions and Equations MCQ Questions with Answers based on the latest NCERT syllabus. Solve important MCQs on photochemical decomposition, silver chloride reactions, corrosion, oxidation, and reaction identification with detailed solutions for CBSE, State Board, Olympiad, and scholarship exams.
Do You Know
Chapter Information
Subject: Science
Class: 10
Chapter: Chemical Reactions and Equations
Question Type: Multiple Choice Questions (MCQs)
Difficulty Level: Moderate to Difficult
Based On: NCERT Latest Syllabus (2026)
Introduction
Chemical reactions can occur due to heat, electricity, light, or direct contact between substances. Understanding how different reactions occur helps students connect chemistry concepts with everyday life and practical applications.
What You Will Learn
✔ Photochemical decomposition
✔ Silver chloride decomposition
✔ Oxidation processes
✔ Corrosion and prevention
✔ Reaction classification
✔ Practical chemistry applications
✔ Conceptual problem-solving
Why This Topic Is Important?
Many natural and industrial processes depend on chemical reactions triggered by light, heat, or electricity. Knowledge of these reactions helps students understand photography, corrosion, food preservation, and several real-life chemical changes.
1. MCQ Questions with Detailed Solutions
Q1. Which reaction takes place when silver chloride is exposed to sunlight?
A) Combination Reaction
B) Decomposition Reaction
C) Displacement Reaction
D) Neutralization Reaction
Answer
B) Decomposition Reaction
Concept Behind This Question
Some compounds decompose when exposed to light energy.
Step-by-Step Solution
Silver chloride decomposes in sunlight:
$$2AgCl \rightarrow 2Ag + Cl_2$$
One compound breaks into simpler substances.
Therefore, it is a decomposition reaction.
Exam Tip
Silver chloride and silver bromide are important examples of photochemical decomposition.
Q2. What is the colour of silver chloride before decomposition?
A) Black
B) Brown
C) White
D) Green
Answer
C) White
Useful Concept for this Question
Silver chloride is a white precipitate that turns grey on exposure to sunlight.
Step-by-Step Solution
Freshly prepared silver chloride appears white.
After exposure to sunlight, it decomposes and darkens due to the formation of silver metal.
Therefore, the correct answer is white.
Exam Tip
NCERT frequently discusses the colour change of silver chloride.
Q3. Which of the following is an example of oxidation in daily life?
A) Freezing of water
B) Rusting of iron
C) Melting of butter
D) Dissolving salt in water
Answer
B) Rusting of iron
Concept Behind This Question
Oxidation involves the addition of oxygen to a substance.
Step-by-Step Solution
During rusting:
Iron combines with oxygen and moisture.
A layer of rust forms on the surface.
Since oxygen is added, rusting is oxidation.
Exam Tip
Rusting is one of the most commonly asked examples of oxidation.
Q4. Which gas is released during the decomposition of silver chloride?
A) Oxygen
B) Hydrogen
C) Nitrogen
D) Chlorine
Answer
D) Chlorine
Useful Formula for this Question
$$2AgCl \rightarrow 2Ag + Cl_2$$
Step-by-Step Solution
According to the equation:
Silver chloride decomposes into silver and chlorine gas.
Therefore, chlorine gas is released.
Exam Tip
Memorize important NCERT decomposition equations.
Q5. Which of the following helps reduce corrosion of metal objects?
A) Keeping them wet
B) Exposing them to moist air
C) Applying protective coatings
D) Storing them in salt water
Answer
C) Applying protective coatings
Concept Behind This Question
Protective layers prevent contact between metal and the environment.
Step-by-Step Solution
Methods such as:
• Painting
• Greasing
• Galvanization
prevent direct exposure to oxygen and moisture.
Therefore, protective coatings reduce corrosion.
Exam Tip
Corrosion can be minimized by preventing contact with air and water.
Important Formulas & Concepts
1. Photochemical Decomposition
Decomposition caused by sunlight.
Example:
$$2AgCl \rightarrow 2Ag + Cl_2$$
2. Oxidation
Addition of oxygen or removal of hydrogen.
3. Corrosion
Gradual deterioration of metals due to environmental reactions.
4. Silver Chloride
A white compound that decomposes in sunlight.
5. Corrosion Prevention
• Painting
• Greasing
• Galvanization
• Protective coatings
Related Practice Questions
- What is photochemical decomposition?
- Why is silver chloride stored away from sunlight?
- Give one example of oxidation in daily life.
- What causes corrosion?
- Name two methods used to prevent corrosion.
Mini Quiz Challenge
Fill in the blanks
- Silver chloride decomposes in the presence of __________.
- Rusting is an example of __________.
- Painting helps prevent __________.
Answers
- Sunlight
- Oxidation
- Corrosion
Exam Tips
✔ Learn important NCERT decomposition reactions.
✔ Remember examples of photochemical reactions.
✔ Revise oxidation and corrosion concepts.
✔ Focus on practical applications of chemistry.
✔ Practice reaction-identification questions.
Quick Revision Notes
✔ Silver chloride undergoes photochemical decomposition.
✔ Silver chloride is white in colour.
✔ Chlorine gas is released during its decomposition.
✔ Rusting is an oxidation reaction.
✔ Corrosion damages metal surfaces.
✔ Protective coatings help prevent corrosion.
✔ Sunlight can initiate certain chemical reactions.
Common Mistakes Students Make
❌ Confusing photochemical decomposition with thermal decomposition.
❌ Forgetting the products of silver chloride decomposition.
❌ Mixing oxidation with corrosion.
❌ Ignoring real-life examples from NCERT.
❌ Memorizing reactions without understanding the concepts.
Key Takeaways
✔ Light can trigger decomposition reactions.
✔ Silver chloride decomposes into silver and chlorine.
✔ Rusting is an oxidation process.
✔ Corrosion damages metals over time.
✔ Protective coatings reduce corrosion.
✔ Photochemical reactions have practical applications.
FAQs
1. What is photochemical decomposition?
A decomposition reaction caused by light energy.
2. Why does silver chloride turn grey in sunlight?
Because metallic silver is formed during decomposition.
3. What is corrosion?
The gradual damage of metals due to chemical reactions with the environment.
4. What is oxidation?
Addition of oxygen or removal of hydrogen.
5. How can corrosion be prevented?
By painting, greasing, galvanization, and protective coatings.
Conclusion Photochemical decomposition, oxidation, and corrosion are important concepts in Chemical Reactions and Equations. Understanding these processes helps students explain many real-life phenomena and strengthens their preparation for CBSE, State Board, Olympiad, and scholarship examinations.
Related links
- Class 10 Social Science Chapter 1 The Rise of Nationalism in Europe part-3
- Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables part-16
- Class 10 Social Science Chapter 1 The Rise of Nationalism in Europe part-2
- Class 10 Science Chapter 1 Chemical Reactions and Equations part-4
- Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables part-15
- Class 10 English Chapter 1 A Triumph of Surgery
- Class 10 Social Science Chapter 1 The Rise of Nationalism in Europe part-1
- Class 10 Science Chapter 1 Chemical Reactions and Equations part-3
- Class 10 Maths Chapter 3 Pair of Linear Equations in Two Variables part-14
- Class 10 Science Chapter 1 Chemical Reactions and Equations part-2
Latest Posts
- Class 9 Maths Chapter 4 Linear Equations in Two Variables
- Class 7 Maths Chapter 4 Simple Equations
- Class 8 Maths Chapter 4 Practical Geometry
- Class 10 Maths Chapter 4 Quadratic Equations
- Class 9 Science Chapter 1 Matter in Our Surroundings
Join Our Other Communities
Instagram , Youtube , Facebook
