CBSE Class 10 Science MCQs, chapter by chapter

1,005 practice questions for CBSE Class 10 Science, organised by NCERT chapter (13 chapters). Every question includes a written explanation. Pick a chapter below, or try the samples first.

CBSE Class 10 Science mock tests and papers

Practice by chapter

Chemical Reactions and Equations

75 questions in timed practice

Acids, Bases and Salts

77 questions in timed practice

Metals and Non-metals

77 questions in timed practice

Carbon and its Compounds

79 questions in timed practice

Life Processes

90 questions in timed practice

Control and Coordination

75 questions in timed practice

How do Organisms Reproduce?

80 questions in timed practice

Heredity

75 questions in timed practice

Light - Reflection and Refraction

75 questions in timed practice

The Human Eye and the Colourful World

75 questions in timed practice

Electricity

77 questions in timed practice

Magnetic Effects of Electric Current

75 questions in timed practice

Our Environment

75 questions in timed practice

Sample questions

Q1
easy
Four household liquids are tested with pH paper: lemon juice, pure water, milk of magnesia and household ammonia solution. Which of them shows the lowest pH?
  1. A Pure water
  2. B Milk of magnesia
  3. C Lemon juice
  4. D Household ammonia solution
Show answer and explanation

Correct answer: C - Lemon juice

The lower the pH, the more acidic the liquid. Lemon juice contains citric acid and has a pH of about $2$, well below the $7$ of pure water. Milk of magnesia and ammonia solution are both basic, with pH values above $7$, so they sit at the opposite end of the scale.
Q2
medium
Assertion (A): An acquired trait such as the muscle strength built up by exercise is passed on to the next generation. Reason (R): A change brought about in the body cells of an animal during its lifetime does not alter the DNA of its germ cells.
  1. A Both A and R are true, and R explains A.
  2. B Both A and R are true, but R does not explain A.
  3. C A is true, but R is false.
  4. D A is false, but R is true.
Show answer and explanation

Correct answer: D - A is false, but R is true.

A is false. Acquired traits are not inherited, which is why the children of a weightlifter are not born with extra muscle. R is true: exercise changes only the body cells, and the DNA carried in the germ cells that make the next generation is left untouched. R is in fact the reason why the claim made in A is wrong.
Q3
medium
Assertion (A): The earth wire of a domestic circuit carries the working current of an appliance while the appliance is running normally. Reason (R): The earth wire is joined to a metal plate buried in the ground and offers a low-resistance path for any current that leaks to the body of an appliance.
  1. A Both A and R are true, and R is the correct explanation of A
  2. B Both A and R are true, but R is not the correct explanation of A
  3. C A is true, but R is false
  4. D A is false, but R is true
Show answer and explanation

Correct answer: D - A is false, but R is true

A is false. During normal working the current goes out along the live wire and returns along the neutral wire, and the earth wire carries nothing. R is true: the earth wire runs to a metal plate buried deep in the ground and provides a low-resistance route for a leakage current, which is why it protects a user only when a fault occurs.
Q4
medium
A dentist uses a mirror to examine the teeth of patients. What type of mirror is he most likely using and why?
  1. A Concave mirror, because it magnifies the image
  2. B Convex mirror, because it gives a wider field of view
  3. C Plane mirror, because it reflects true size images
  4. D Convex mirror, because it diverges light
Show answer and explanation

Correct answer: A - Concave mirror, because it magnifies the image

Dentists use concave mirrors because they can produce magnified images of the teeth, making it easier to see details. Convex mirrors diverge light and are used for wide-field views, which is unnecessary here.
Q5
medium
A student adds dilute hydrochloric acid to sodium carbonate. What are the products formed in this reaction?
  1. A Sodium hydroxide, carbon dioxide, water
  2. B Sodium sulfate, hydrogen gas
  3. C Sodium carbonate, hydrogen gas
  4. D Sodium chloride, carbon dioxide, water
Show answer and explanation

Correct answer: D - Sodium chloride, carbon dioxide, water

Sodium carbonate reacts with dilute hydrochloric acid to produce sodium chloride, carbon dioxide, and water. Sodium hydroxide and hydrogen gas are not products of this reaction, and sodium sulfate is not involved in the reaction.
Q6
medium
Which of these everyday changes is an example of reduction?
  1. A A cut apple turns brown after being left in the air
  2. B A silver spoon slowly develops a black coating
  3. C Butter kept in a warm room develops an unpleasant smell
  4. D Iron ore is heated with coke in a furnace and iron metal is obtained
Show answer and explanation

Correct answer: D - Iron ore is heated with coke in a furnace and iron metal is obtained

Heating iron ore with coke removes oxygen from the iron oxide, and loss of oxygen is reduction. The other three are oxidations: the cut apple and the butter both react with the oxygen of the air, and the black coating on silver forms when silver reacts with substances present in the air.

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