In this article, we will cover Class 9 Chemistry MCQs. Based on the NCERT syllabus, this section includes essential topics such as Matter in Our Surroundings, Is Matter Around Us Pure, Atoms and Molecules, Structure of the Atom, and Chemical Reactions. Practicing these MCQs will help students strengthen their understanding of fundamental concepts, enhance problem-solving abilities, and prepare effectively for exams.
1. What is matter?
a) Anything that has mass and occupies space
b) Anything that can be touched
c) Only solids that occupy space
d) Only gases with mass
View Answer
Explanation: Matter is anything that has mass and occupies space, regardless of its state. It can exist as solid, liquid, or gas, and is the substance that makes up everything around us.
2. What is the basic unit of matter?
a) Proton
b) Molecule
c) Atom
d) Neutron
View Answer
Explanation: The basic unit of matter is the atom. Atoms combine to form molecules, and these molecules form all matter we see around us.
3. Which of the following is NOT a property of matter?
a) Volume
b) Temperature
c) Mass
d) Color
View Answer
Explanation: Temperature is not considered a fundamental property of matter. Matter has intrinsic properties like mass, volume, and color, but temperature is an external factor that affects its state.
4. What is the characteristic of gases?
a) Fixed shape and fixed volume
b) Fixed volume but no fixed shape
c) No fixed volume or shape
d) Fixed shape but no fixed volume
View Answer
Explanation: Gases have no definite shape or volume. They expand to fill the entire space available in a container, moving freely and rapidly.
5. What is plasma?
a) A solid state of matter
b) A liquid state of matter
c) A gaseous state with no particles
d) A state of matter with charged particles
View Answer
Explanation: Plasma is a state of matter where the gas is ionized, meaning it contains charged particles (ions and electrons) and is often found in high-energy environments like stars or lightning.
6. Which state of matter has no definite shape but a definite volume?
a) Solid
b) Liquid
c) Gas
d) Plasma
View Answer
Explanation: Liquids have a definite volume, but their particles are not fixed in place. This allows liquids to flow and take the shape of their container, but they don’t change their volume.
7. What is sublimation?
a) Solid to gas
b) Gas to solid
c) Liquid to solid
d) Liquid to gas
View Answer
Explanation: Sublimation is the process where a substance changes directly from a solid to a gas, bypassing the liquid phase entirely. A common example is dry ice (solid carbon dioxide).
8. Which of the following processes involves the change of gas into a liquid?
a) Evaporation
b) Freezing
c) Condensation
d) Melting
View Answer
Explanation: Condensation occurs when gas cools down and transitions into a liquid. This process is commonly observed when water vapor turns into liquid water on cold surfaces.
9. What is the boiling point of water?
a) 0°C
b) 100°C
c) 50°C
d) 200°C
View Answer
Explanation: The boiling point of water is 100°C at standard atmospheric pressure. At this temperature, water turns from a liquid into a gas (steam).
10. Which of the following changes is reversible?
a) Melting of wax
b) Burning of paper
c) Rusting of iron
d) Cooking of food
View Answer
Explanation: Melting of wax is a reversible change because, when cooled, the wax solidifies again. In contrast, burning, rusting, and cooking are irreversible processes.
11. What is the main cause of evaporation?
a) Decrease in temperature
b) Increase in pressure
c) Increase in temperature
d) Decrease in volume
View Answer
Explanation: Evaporation occurs when heat is applied, increasing the energy of particles in a liquid. This allows some particles to escape into the air as vapor, especially when the temperature rises.
12. Which of the following substances is a pure element?
a) Copper
b) Sodium chloride
c) Air
d) Saltwater
View Answer
Explanation: Copper is a pure element, meaning it consists of only copper atoms. Sodium chloride, air, and saltwater are mixtures or compounds.
13. What is the key characteristic of a heterogeneous mixture?
a) Components are uniformly distributed
b) Components are chemically bonded
c) Components form a single phase
d) Components are not uniformly distributed
View Answer
Explanation: In a heterogeneous mixture, the components are not uniformly distributed, and the different substances can be physically separated.
14. What is a colloid?
a) A solution in which the solute is in large quantities
b) A homogeneous mixture with small particles
c) A heterogeneous mixture with tiny particles
d) A homogeneous mixture with large particles
View Answer
Explanation: A colloid is a heterogeneous mixture where the particles are small enough to remain suspended in the mixture, scattering light, but are not large enough to settle out.
15. Which of the following is an example of a pure substance?
a) Hydrogen
b) Salt solution
c) Sand and water
d) Air
View Answer
Explanation: Hydrogen is a pure substance consisting only of hydrogen atoms, while the others are mixtures.
16. What type of mixture is air?
a) Heterogeneous mixture
b) Homogeneous mixture
c) Compound
d) Pure substance
View Answer
Explanation: Air is a homogeneous mixture because its components (gases like oxygen and nitrogen) are uniformly distributed and cannot be seen or separated easily.
17. Which of the following is an example of a heterogeneous mixture?
a) Concrete
b) Vinegar
c) Milk
d) Saltwater
View Answer
Explanation: Concrete is a heterogeneous mixture because its components (such as sand, water, and cement) are visible and not uniformly distributed.
18. Which of the following is an example of a compound?
a) Saltwater
b) Oxygen
c) Sand
d) Water
View Answer
Explanation: Water is a compound made up of hydrogen and oxygen atoms in fixed proportions, unlike the other options, which are either mixtures or elements.
19. What is the main characteristic of a homogeneous mixture?
a) The components settle over time
b) The components are visibly different
c) The components are uniformly distributed
d) The components can be separated by physical means
View Answer
Explanation: A homogeneous mixture has components that are uniformly distributed, making it appear as a single phase throughout.
20. Which of the following is a technique used to separate different colored pigments in a mixture?
a) Distillation
b) Chromatography
c) Filtration
d) Centrifugation
View Answer
Explanation: Chromatography is used to separate components of a mixture, such as pigments, based on their differing rates of movement through a medium.
21. What is an atom?
a) The smallest particle of an element
b) A particle of a compound
c) A type of molecule
d) A part of a molecule
View Answer
Explanation: An atom is the smallest unit of an element that retains its chemical properties. Molecules are made up of atoms.
22. Which of the following particles are found in the nucleus of an atom?
a) Only neutrons
b) Electrons and neutrons
c) Protons and neutrons
d) Electrons and protons
View Answer
Explanation: The nucleus of an atom contains protons and neutrons, while electrons orbit the nucleus in electron shells.
23. Which of the following is a molecule made up of two identical atoms?
a) Water (H2O)
b) Oxygen (O2)
c) Methane (CH4)
d) Carbon dioxide (CO2)
View Answer
Explanation: Oxygen (O2) consists of two identical oxygen atoms bonded together, forming a diatomic molecule. The other molecules listed are made up of different elements or more than two atoms.
24. What is the empirical formula of glucose (C6H12O6)?
a) C6H12O6
b) CH2O
c) CH3O
d) C12H2O12
View Answer
Explanation: The empirical formula of glucose represents the simplest ratio of the elements. The simplest ratio of carbon, hydrogen, and oxygen in glucose is CH2O, which is the empirical formula.
25. Which of the following is a diatomic molecule?
a) Oxygen (O2)
b) Nitrogen (N2)
c) Chlorine (Cl2)
d) All of the mentioned
View Answer
Explanation: All of the listed molecules O2, N2, and Cl2 are diatomic, meaning they consist of two atoms of the same element.
26. Which of the following elements is inert?
a) Oxygen
b) Neon
c) Nitrogen
d) Hydrogen
View Answer
Explanation: Neon is an inert (noble) gas, meaning it is chemically stable and unreactive due to having a full outer electron shell.
27. What is the formula of sodium chloride?
a) Na2Cl
b) NaCl2
c) NaCl
d) Na2Cl2
View Answer
Explanation: Sodium chloride, or common salt, has the formula NaCl. It is formed by the combination of sodium (Na) and chlorine (Cl) in a 1:1 ratio.
28. Which subatomic particle has a negative charge?
a) Neutron
b) Electron
c) Proton
d) Both proton and electron
View Answer
Explanation: Electrons carry a negative charge, while protons have a positive charge, and neutrons are neutral.
29. What is the chemical formula for calcium chloride?
a) CaCl
b) Ca2Cl2
c) Ca2Cl
d) CaCl2
View Answer
Explanation: The chemical formula for calcium chloride is CaCl2, indicating that one calcium atom bonds with two chloride ions.
30. What is the bond formed when two atoms share electrons?
a) Ionic bond
b) Metallic bond
c) Covalent bond
d) Hydrogen bond
View Answer
Explanation: A covalent bond is formed when two atoms share electrons in order to achieve a stable electron configuration. This is typical in nonmetals.
31. What is the molar mass of carbon dioxide (CO2)?
a) 44 g/mol
b) 18 g/mol
c) 28 g/mol
d) 22 g/mol
View Answer
Explanation: The molar mass of CO2 is 44 g/mol, calculated as 12 g/mol for carbon and 16 g/mol for each oxygen atom (16 × 2 = 32 g/mol).
32. What does the law of conservation of mass state?
a) Mass is gained during a chemical reaction
b) Mass remains constant during a chemical reaction
c) Mass can be created in a chemical reaction
d) Mass is lost during a chemical reaction
View Answer
Explanation: The law of conservation of mass states that the total mass of the reactants equals the total mass of the products in any chemical reaction, meaning mass is neither created nor destroyed.
33. What is formed when an acid reacts with a base?
a) Salt
b) Oxygen
c) Water
d) Carbon dioxide
View Answer
Explanation: When an acid reacts with a base, it undergoes a neutralization reaction, producing a salt and water. This is a fundamental concept in acid-base chemistry.
34. What is the mass of a neutron?
a) 1 kg
b) 9.1 × 10-31 kg
c) 1 amu
d) 0 amu
View Answer
Explanation: A neutron has a mass of approximately 1 atomic mass unit (amu), which is nearly identical to the mass of a proton. The mass is much larger than that of an electron.
35. How does the mass number of an atom change when it undergoes beta decay?
a) It decreases by 1
b) It stays the same
c) It doubles
d) It increases by 1
View Answer
Explanation: In beta decay, a neutron in the nucleus of an atom is converted into a proton. The mass number remains the same because a neutron and proton have almost the same mass, but the atomic number increases by 1.
36. The electron configuration of sodium (Na) is 2, 8, 1. What is the number of electrons in the outermost shell of sodium?
a) 10
b) 2
c) 1
d) 8
View Answer
Explanation: Sodium (Na) has 1 electron in its outermost shell. This is why it is reactive and tends to lose this electron to achieve a stable electron configuration.
37. Which of the following is true about the electron?
a) It has a positive charge
b) It is located in the nucleus
c) It has a mass equal to that of a proton
d) It is found in orbitals outside the nucleus
View Answer
Explanation: Electrons are found in orbitals around the nucleus and have a negative charge. Their mass is much smaller than that of protons and neutrons.
38. What is the atomic mass unit (amu) based on?
a) Mass of carbon-12 isotope
b) Mass of a proton
c) Mass of a neutron
d) Mass of an electron
View Answer
Explanation: The atomic mass unit (amu) is based on the mass of the carbon-12 isotope, with one amu being defined as one twelfth of the mass of a carbon-12 atom.
39. What is the charge of an atom that has 10 protons, 10 electrons, and 12 neutrons?
a) Positive
b) Negative
c) Neutral
d) Undefined
View Answer
Explanation: An atom with an equal number of protons and electrons is neutral. The number of neutrons does not affect the overall charge.
40. Which of the following atomic models does not depict the structure of the atom accurately?
a) Rutherford’s model
b) Thomson’s model
c) Bohr’s model
d) Dalton’s model
View Answer
Explanation: Dalton’s model proposed the atom as indivisible, which was later disproven by the discovery of subatomic particles. It doesn’t accurately describe atomic structure.
41. Which of the following does not conduct electricity?
a) Copper
b) Plastic
c) Water
d) Iron
View Answer
Explanation: Plastic is an insulator and does not conduct electricity, unlike copper, iron, and water, which are conductors under certain conditions.
42. What is the maximum number of electrons in the third shell of an atom?
a) 32
b) 8
c) 18
d) 2
View Answer
Explanation: The third shell can hold up to 18 electrons. The electron capacity of shells increases as you move outward from the nucleus.
43. What is the principal cause of the atomic spectra produced by elements?
a) Electrons jumping from lower to higher energy levels
b) Protons emitting radiation
c) Electrons moving in circular orbits
d) Electrons changing position within an orbital
View Answer
Explanation: Atomic spectra are caused by electrons transitioning between energy levels within the atom, emitting light at specific wavelengths.
44. Which of the following is an example of an element that exists as isotopes?
a) Hydrogen
b) Oxygen
c) Carbon
d) All of the mentioned
View Answer
Explanation: All of the elements listed—hydrogen, oxygen, and carbon—have isotopes. Isotopes are atoms of the same element that differ in the number of neutrons.
Explore Class 9 Chemistry MCQs Chapter-wise
Explore more MCQs chapter-wise below and test your understanding of each topic in greater detail:
- Matter in Our Surroundings MCQ
- Is Matter Around Us Pure MCQ
- Atoms and Molecules MCQ
- Structure of Atom MCQ
Related Links:
Frequently Asked Questions (FAQs) About Class 9 Chemistry MCQs
Q1. What topics are covered in Class 9 Chemistry MCQs?
The MCQs cover all major topics in the Class 9 Chemistry syllabus, such as:
- Matter in Our Surroundings
- Is Matter Around Us Pure
- Atoms and Molecules
- Structure of the Atom
Q2. Are these MCQs based on the NCERT syllabus?
Yes, the MCQs are curated in alignment with the NCERT syllabus to help students effectively prepare for school and board-level exams.
Q3. Do these MCQs include numerical problems?
Yes, topics like molecular mass, mole concept, and concentration of solutions include numerical-based MCQs.
Q4. Why should I practice Class 9 Chemistry MCQs?
Practicing Class 9 Chemistry MCQs strengthens your understanding of key concepts, improves problem-solving speed, and boosts exam confidence.
Q5. Are these Chemistry MCQs useful for competitive exams?
Yes, they are useful for competitive exams like NTSE and Olympiads, as they help improve concept application, time management, and exam readiness.
