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Practice Class 8 Science MCQ Questions with Answers based on the latest NCERT syllabus. Learn about biodegradable and non-biodegradable materials, metals and acids, soil preparation, yeast, alcohol production, and human reproduction with detailed solutions for CBSE and State Board exams.
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Chapter Information
Subject: Science
Class: 8
Topics Covered:
- Synthetic Fibres and Plastics
- Crop Production and Management
- Microorganisms: Friend and Foe
- Materials: Metals and Non-metals
- Reaching the Age of Adolescence
Question Type: Multiple Choice Questions (MCQs)
Difficulty Level: Easy to Moderate
Based On: Latest NCERT Syllabus
Introduction
Science helps us understand the materials we use, how crops are cultivated, the role of microorganisms, chemical reactions, and the process of human growth and development. These concepts are important for daily life as well as school examinations. Regular MCQ practice strengthens conceptual understanding and improves problem-solving skills.
What You Will Learn
✔ Biodegradable and non-biodegradable materials
✔ Reaction of metals with acids
✔ Soil preparation before sowing
✔ Role of yeast in alcohol production
✔ Stages of human development before birth
✔ Important NCERT concepts
Why This Topic Is Important?
These concepts help students understand environmental protection, agriculture, industrial applications of microorganisms, chemical reactions, and human development. Questions from these topics are frequently asked in CBSE, State Board, Olympiad, and scholarship examinations.
Exam Relevance
These questions are useful for:
✔ CBSE Exams
✔ State Board Exams
✔ School Tests
✔ Unit Tests
✔ Half-Yearly Exams
✔ Annual Exams
✔ Scholarship Examinations
Q1. Which of the following is a non-biodegradable material?
A) Cotton cloth
B) Paper
C) Fruit peels
D) Plastic bags
Answer: Plastic bags
Concept Behind This Question
Non-biodegradable materials cannot be decomposed naturally by microorganisms.
Step-by-Step Solution
Cotton cloth, paper, and fruit peels decompose naturally over time.
Plastic bags remain in the environment for many years because microorganisms cannot break them down easily.
Therefore, the correct answer is: Plastic bags.
Exam Tip
Remember:
Plastic → Non-biodegradable
Paper & Cotton → Biodegradable
Q2. Metals react with acids to produce which gas?
A) Nitrogen gas
B) Hydrogen gas
C) Carbon dioxide
D) Oxygen gas
Answer: Hydrogen gas
Useful Formula for This Question
Metal + Acid → Salt + Hydrogen Gas (H₂)
Concept Behind This Question
Most reactive metals react with dilute acids to release hydrogen gas.
Step-by-Step Solution
When a metal reacts with a dilute acid, a salt is formed along with hydrogen gas.
Example:
Zn + 2HCl → ZnCl₂ + H₂↑
Therefore, the correct answer is: Hydrogen gas.
Exam Tip
If hydrogen gas is produced, it burns with a characteristic ‘pop’ sound during the laboratory test.
Q3. The process of loosening and turning of the soil is called:
A) Sowing
B) Harvesting
C) Tilling or Ploughing
D) Levelling
Answer: Tilling or Ploughing
Concept Behind This Question
The first step in crop production is preparing the soil.
Step-by-Step Solution
Tilling or ploughing loosens the soil, improves aeration, and allows roots to grow deeply.
It also helps mix manure and nutrients uniformly into the soil.
Therefore, the correct answer is: Tilling or Ploughing.
Exam Tip
Preparation of soil is always done before sowing seeds.
Q4. Which of the following is used for the production of alcohol?
A) Sodium bicarbonate
B) Yeast
C) Hydrochloric acid
D) Nitrogen
Answer: Yeast
Concept Behind This Question
Yeast converts sugar into alcohol through fermentation.
Step-by-Step Solution
Yeast is a useful microorganism used in brewing industries.
It converts sugar into alcohol and carbon dioxide in the absence of oxygen.
Hydrochloric acid, sodium bicarbonate, and nitrogen are not used for alcohol production.
Therefore, the correct answer is: Yeast.
Exam Tip
Remember:
Yeast → Fermentation → Alcohol Production
Q5. The stage of the embryo in which all the body parts can be identified is called:
A) Fetus
B) Zygote
C) Egg
D) Sperm
Answer: Fetus
Concept Behind This Question
As the embryo develops, it reaches a stage where all major body organs become identifiable.
Step-by-Step Solution
After continuous growth, the embryo develops into a fetus.
At the fetal stage, major body parts such as hands, legs, eyes, ears, and other organs can be recognized.
Therefore, the correct answer is: Fetus.
Exam Tip
Remember the sequence:
Zygote → Embryo → Fetus → Baby
Important Formulas & Concepts
1. Biodegradable Materials
Materials that can be decomposed naturally by microorganisms.
Examples: Paper, Cotton, Fruit peels
2. Non-Biodegradable Materials
Materials that cannot be decomposed easily by microorganisms.
Examples: Plastic, Glass, Polythene
3. Reaction of Metals with Acids
Metal + Acid → Salt + Hydrogen Gas
Example:
Zn + 2HCl → ZnCl₂ + H₂↑
4. Preparation of Soil
The first agricultural operation is Tilling (Ploughing).
Benefits:
- Improves aeration
- Helps root growth
- Mixes manure evenly
5. Fermentation
Sugar → Alcohol + Carbon Dioxide (by Yeast)
6. Human Development Stages
Zygote → Embryo → Fetus → Baby
Related Practice Questions
- Name two biodegradable materials.
- Which gas is released when zinc reacts with hydrochloric acid?
- Why is tilling important before sowing seeds?
- What is fermentation?
- What is the difference between an embryo and a fetus?
Mini Quiz Challenge
True or False
- Plastic bags are biodegradable.
- Metals produce hydrogen gas when reacting with dilute acids.
- Ploughing is done after harvesting.
- Yeast is used in alcohol production.
- A fetus has identifiable body organs.
Exam Tips
✔ Learn the difference between biodegradable and non-biodegradable materials.
✔ Remember the reaction of metals with dilute acids.
✔ Revise the sequence of human development.
✔ Understand the importance of tilling in agriculture.
✔ Memorize the role of yeast in fermentation.
Quick Revision Notes
✔ Plastic bags are non-biodegradable.
✔ Metals react with acids to release hydrogen gas.
✔ Tilling prepares the soil for cultivation.
✔ Yeast is used to produce alcohol.
✔ Fetus is the stage where body organs are identifiable.
✔ Fermentation converts sugar into alcohol.
Common Mistakes Students Make
❌ Confusing biodegradable materials with non-biodegradable materials.
❌ Selecting carbon dioxide instead of hydrogen gas.
❌ Thinking sowing is the first agricultural activity.
❌ Confusing yeast with chemicals used in laboratories.
❌ Mixing up the stages of zygote, embryo, and fetus.
Key Takeaways
- Plastic bags are non-biodegradable and cause environmental pollution.
- Metals react with dilute acids to produce hydrogen gas.
- Tilling is the first step in crop production.
- Yeast is essential for alcohol production through fermentation.
- A fetus has recognizable body parts during development.
FAQs
1. Which material is non-biodegradable?
Plastic bags are non-biodegradable.
2. Which gas is produced when metals react with acids?
Hydrogen gas is produced.
3. What is tilling?
Tilling is the process of loosening and turning the soil before sowing.
4. Which microorganism is used to produce alcohol?
Yeast is used for alcohol production through fermentation.
5. What is a fetus?
A fetus is the stage of development in which all major body parts can be identified.
Conclusion
This Class 8 Science MCQ Practice Set covers important NCERT concepts from environmental science, agriculture, microorganisms, chemical reactions, and human development. Solving these questions regularly helps students strengthen their concepts, improve analytical thinking, and score better in school as well as competitive examinations.
NCERT Reference
Book: NCERT Science Class 8
Relevant Chapters:
- Chapter 3 – Synthetic Fibres and Plastics
- Chapter 1 – Crop Production and Management
- Chapter 2 – Microorganisms: Friend and Foe
- Chapter 4 – Materials: Metals and Non-metals
- Chapter 10 – Reaching the Age of Adolescence
Based On: Latest NCERT Curriculum (CBSE)
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