NCERT Solutions
Class 10 Science
13 chapters · 52 important questions
Chemical Reactions and Equations
Introduces chemical equations and types of chemical reactions — combination, decomposition, displacement, double displacement, oxidation and reduction. Writing and balancing chemical equations is the core skill.
Key Topics
Important Questions
Write a balanced chemical equation with state symbols for: (a) Burning of magnesium ribbon in air (b) Decomposition of ferrous sulphate crystals.
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
What is a redox reaction? Give one example.
Define corrosion. How can it be prevented?
Acids, Bases and Salts
Covers chemical properties of acids and bases, the pH scale, and formation of salts. Important salts (NaCl, NaHCO₃, Na₂CO₃, bleaching powder) and their uses are frequently asked in board exams.
Key Topics
Important Questions
Why does tooth decay start when the pH of the mouth falls below 5.5?
What is a neutralisation reaction? Give one example from daily life.
How is baking soda different from washing soda? Give chemical formulae and one use of each.
What happens when a metal carbonate reacts with acid? Write equation for marble and hydrochloric acid.
Metals and Non-metals
Compares physical and chemical properties of metals and non-metals. The reactivity series and its applications (thermite reaction, extraction of metals) are key. Ionic bond formation is introduced.
Key Topics
Important Questions
Write the steps involved in the extraction of a highly reactive metal like aluminium from its ore.
What is the thermite reaction? State its one industrial application.
Why are ionic compounds good conductors of electricity in solution but not in solid state?
How does the reactivity series help in explaining the displacement reactions?
Carbon and its Compounds
Covers covalent bonding in carbon compounds, homologous series, and functional groups. Ethanol, ethanoic acid, soaps, and detergents are important applied topics frequently asked in board exams.
Key Topics
Important Questions
What is a homologous series? Give two characteristics and the first three members of the alkane series.
Explain the cleansing action of soaps. Why do soaps not work well in hard water?
Write the structural formula of ethanoic acid. What happens when sodium hydrogen carbonate is added to it?
What is saponification? Write the equation.
Life Processes
Covers nutrition, respiration, transportation, and excretion in humans and plants. The structure and function of the heart, kidney, and leaf (for photosynthesis) are diagram-heavy topics.
Key Topics
Important Questions
Draw a well-labelled diagram of the human heart and describe how blood is pumped through the body.
Explain the process of photosynthesis. What is the significance of stomata?
What is the role of kidneys in human beings? Explain with the help of a labelled diagram.
How is aerobic respiration different from anaerobic respiration?
Control and Coordination
Covers the nervous system (neuron structure, reflex arc, brain regions) and the endocrine system (hormones and their functions) in animals. Movement in plants (tropic and nastic) is also included.
Key Topics
Important Questions
Draw a labelled diagram of a neuron. Explain how nerve impulse travels across a synapse.
What is a reflex action? Give one example and draw the reflex arc.
Compare the nervous and hormonal systems of coordination.
What is phototropism? Explain with a labelled diagram.
How do Organisms Reproduce?
Covers asexual and sexual reproduction in plants and animals. Reproduction in humans (male and female reproductive systems) and contraception are included. Puberty and STDs are also covered.
Key Topics
Important Questions
Draw a diagram of the human male reproductive system and label any four parts.
Distinguish between sexual and asexual reproduction. Give two advantages of sexual reproduction.
What are the different methods of contraception?
Explain vegetative propagation with two examples.
Heredity
Covers Mendel's laws of inheritance using monohybrid and dihybrid crosses. Chromosomes as carriers of hereditary information, sex determination, and evolution (Darwin's theory) are included.
Key Topics
⚠️ Deleted from Syllabus 2025-26
- — Evolution chapter merged into Heredity — speciation and molecular phylogeny
Important Questions
What are Mendel's laws of inheritance? Explain the law of segregation with a monohybrid cross.
In humans, sex is determined by sex chromosomes. Explain how.
How does the creation of variations in a species promote survival?
A tall pea plant (TT) is crossed with a short pea plant (tt). What would be the phenotypic ratio in the F2 generation?
Light – Reflection and Refraction
Covers reflection by spherical mirrors (concave and convex) and refraction through lenses (convex and concave). Mirror formula, lens formula, and magnification are key numerical topics.
Key Topics
Important Questions
An object 5 cm in length is placed 25 cm in front of a concave mirror of focal length 10 cm. Find the position, size and nature of the image.
Explain with a ray diagram how a convex lens forms a real and inverted image when the object is beyond 2F.
The refractive index of glass is 1.5. What is the speed of light in glass?
A concave lens has a focal length of 15 cm. At what distance should an object be placed so that it forms an image at 10 cm from the lens?
The Human Eye and the Colourful World
Covers structure and function of the human eye, defects of vision and their correction, refraction through a glass prism, and dispersion of light. The phenomena of rainbow, atmospheric refraction are also included.
Key Topics
Important Questions
Draw a labelled diagram of the human eye. Explain how it adjusts its focal length to see objects at different distances.
A person cannot see objects closer than 1 m. What is his defect and how can it be corrected?
Explain why the sky appears blue during the day and the sun appears red at sunrise/sunset.
What is the Tyndall effect? Give one example from nature.
Electricity
Covers Ohm's law, resistance and resistivity, and series/parallel combination of resistors. Heating effect of current (Joule's law) and electric power are key numerical topics.
Key Topics
Important Questions
Draw a circuit diagram for three resistors connected in parallel. Derive the equivalent resistance.
An electric bulb is rated 220V and 100W. When it is operated at 110V, what power will it consume?
Why are copper and aluminium wires generally used for electricity transmission?
How much heat will be generated by a 40W electric heater in 1 hour?
Magnetic Effects of Electric Current
Covers magnetic field due to current in a straight conductor, solenoid, and toroid. Fleming's rules, electric motor, electromagnetic induction, and AC/DC generators are included.
Key Topics
Important Questions
Draw a labelled diagram of an AC generator and explain how it works.
State Fleming's left hand rule. Give one application.
What is electromagnetic induction? State Faraday's law.
Why is it important to have earthing in domestic electrical circuits?
Our Environment
Covers food chains, food webs, trophic levels, and ecosystem. Ozone layer depletion, management of garbage, and biodegradable vs non-biodegradable waste are environmental topics asked in exams.
Key Topics
⚠️ Deleted from Syllabus 2025-26
- — Management of natural resources chapter removed from Class 10 syllabus 2025-26
Important Questions
What is biological magnification? Why does it occur at higher trophic levels?
How does ozone layer depletion occur? What are its harmful effects?
Construct a food chain with four trophic levels using organisms of a grassland ecosystem.
Why is the flow of energy in an ecosystem unidirectional?