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Practice Class 10 Science MCQ Questions with Answers based on the latest NCERT syllabus. Learn about decomposition reactions, bleaching powder, cerebellum, transpiration, and mercury through detailed concept-based explanations, exam tips, and original NCERT-aligned solutions for CBSE and State Board students.
Do You Know
Chapter Information
Subject: Science
Class: 10
Chapters Covered:
- Chemical Reactions and Equations
- Acids, Bases and Salts
- Control and Coordination
- Life Processes
- Metals and Non-Metals
Question Type: Multiple Choice Questions (MCQs)
Difficulty Level: Moderate
Based On: Latest NCERT Syllabus
Introduction
Science helps us understand the natural world through observation, experiments, and logical reasoning. In Class 10, students study important concepts from Chemistry, Biology, and Physics that form the foundation for higher education. Regular MCQ practice strengthens conceptual understanding and improves confidence for school and board examinations.
What You Will Learn
✔ Decomposition reactions
✔ Chemical formula of bleaching powder
✔ Function of the cerebellum
✔ Process of transpiration
✔ Liquid metals at room temperature
Why This Topic Is Important?
These concepts are frequently tested in CBSE and State Board examinations. A clear understanding of chemical reactions, plant physiology, human nervous system functions, and the properties of metals helps students solve both objective and descriptive questions accurately.
Exam Relevance
Useful for:
✔ CBSE Board Exams
✔ State Board Exams
✔ School Tests
✔ Unit Tests
✔ Pre-Board Exams
✔ Annual Exams
✔ Scholarship Exams
Q1. Which of the following is a decomposition reaction?
A) $$\mathrm{NaOH + HCl \rightarrow NaCl + H_2O}$$
B) $$\mathrm{H_2 + Cl_2 \rightarrow 2HCl}$$
C) $$\mathrm{Zn + CuSO_4 \rightarrow ZnSO_4 + Cu}$$
D) $$2H_2O \xrightarrow{\text{Electricity}}2H_2+O_2$$
Answer
$$2H_2O \xrightarrow{\text{Electricity}}2H_2+O_2$$
Concept
A decomposition reaction occurs when one compound breaks down into two or more simpler substances by the action of heat, light, or electricity.
Detailed Explanation
In this reaction, electric current decomposes water into hydrogen and oxygen gases. This process is known as electrolysis of water. Since one compound splits into simpler products, it is classified as a decomposition reaction.
Exam Focus
Remember the four major reaction types:
- Combination
- Decomposition
- Displacement
- Double Displacement
Q2. What is the chemical formula of Bleaching Powder?
A) $$\mathrm{Ca(OH)_2}$$
B) $$\mathrm{CaOCl_2}$$
C) $$\mathrm{CaCO_3}$$
D) $$\mathrm{CaO}$$
Answer:
$$\mathrm{CaOCl_2}$$
Concept
Bleaching powder is an important industrial chemical used for bleaching and disinfecting purposes.
Detailed Explanation
Bleaching powder, chemically represented as CaOCl₂, is commonly used to disinfect drinking water and bleach cotton, linen, and paper. It is manufactured using chlorine and dry slaked lime.
Exam Focus
Remember these formulas:
- Bleaching Powder → CaOCl₂
- Slaked Lime → Ca(OH)₂
- Quick Lime → CaO
Q3. Which part of the brain maintains the posture and balance of the body?
A) Pons
B) Cerebellum
C) Cerebrum
D) Medulla
Answer
Cerebellum
Concept
Different regions of the brain control different body functions.
Detailed Explanation
The cerebellum coordinates voluntary muscle movements and maintains posture, balance, and body coordination. It allows smooth and controlled movement during activities such as walking, running, and writing.
Exam Focus
Remember:
Cerebellum = Balance + Coordination
Q4. The process of loss of water in the form of vapour from the aerial parts of the plant is called:
A) Transpiration
B) Excretion
C) Photosynthesis
D) Respiration
Answer
Transpiration
Concept
Plants continuously lose water vapour through tiny pores called stomata.
Detailed Explanation
Transpiration is the evaporation of water from the aerial parts of plants, mainly through stomata. This process helps in transporting water and minerals from roots to leaves, cools the plant, and supports normal physiological functions.
Exam Focus
Remember:
Water Vapour Loss from Plants = Transpiration
Q5. Which of the following metals exists in a liquid state at room temperature?
A) Aluminum
B) Mercury
C) Sodium
D) Magnesium
Answer
Mercury
Concept
Most metals remain solid at room temperature, but mercury is an important exception.
Detailed Explanation
Mercury (Hg) is the only common metal that remains liquid at room temperature. Because of its unique physical properties, it was traditionally used in thermometers, barometers, and laboratory instruments.
Exam Focus
Remember:
Mercury = Liquid Metal at Room Temperature
Important Formulas & Concepts
Types of Chemical Reactions
- Combination Reaction
- Decomposition Reaction
- Displacement Reaction
- Double Displacement Reaction
- Neutralisation Reaction
- Redox Reaction
Important Chemical Formula
Bleaching Powder = CaOCl₂
Brain Functions
- Cerebrum → Thinking and memory
- Cerebellum → Balance and coordination
- Medulla → Involuntary actions
- Pons → Relay of nerve signals
Transpiration
Loss of water vapour from the aerial parts of plants through stomata.
Liquid Metal
Mercury (Hg) is the common liquid metal at room temperature.
Related Practice Questions
- What are the different types of chemical reactions?
- Write two uses of bleaching powder.
- What is the function of the cerebellum?
- Why is transpiration important for plants?
- Name one non-metal that exists in the liquid state at room temperature.
Mini Quiz Challenge
True or False
- Water decomposes into hydrogen and oxygen during electrolysis.
- Bleaching powder has the chemical formula CaOCl₂.
- Cerebellum controls body balance.
- Transpiration mainly occurs through stomata.
- Mercury is liquid at room temperature.
Exam Tips
✔ Learn important chemical formulas.
✔ Identify reaction types from equations.
✔ Revise the functions of each part of the brain.
✔ Understand the role of transpiration in plants.
✔ Memorize important physical properties of metals.
Quick Revision Notes
✔ Decomposition reaction breaks one compound into simpler substances.
✔ Bleaching Powder → CaOCl₂.
✔ Cerebellum maintains balance and posture.
✔ Transpiration occurs mainly through stomata.
✔ Mercury is liquid at room temperature.
Common Mistakes Students Make
❌ Confusing decomposition and displacement reactions.
❌ Mixing up bleaching powder with slaked lime.
❌ Confusing cerebrum and cerebellum.
❌ Treating transpiration and respiration as the same process.
❌ Forgetting that mercury is liquid at room temperature.
Key Takeaways
- Decomposition reactions split a compound into simpler substances.
- Bleaching powder has the formula CaOCl₂.
- The cerebellum maintains balance and coordination.
- Transpiration helps transport water and regulate plant temperature.
- Mercury is the only common metal that is liquid at room temperature.
FAQs
1. What is a decomposition reaction?
A decomposition reaction is a chemical reaction in which one compound breaks down into two or more simpler substances.
2. What is the chemical formula of bleaching powder?
The chemical formula of bleaching powder is CaOCl₂.
3. Which part of the brain controls balance?
The cerebellum controls balance, posture, and coordination.
4. What is transpiration?
Transpiration is the loss of water vapour from the aerial parts of plants through stomata.
5. Which metal remains liquid at room temperature?
Mercury (Hg) is the common metal that remains liquid at room temperature.
Conclusion
Understanding the concepts of chemical reactions, important chemical compounds, plant physiology, the nervous system, and the properties of metals is essential for success in Class 10 Science. Regular practice of concept-based MCQs strengthens analytical thinking, improves retention, and builds confidence for board examinations.
NCERT Reference
Book: NCERT Science Class 10
Based On: Latest NCERT Curriculum (CBSE)
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