Chemistry Multiple Choice Question And Answers
Question 1. Air is a/an
- element
- compound
- mixture
- colloid
Answer. 3. mixture
Question 2. All the following are examples of chemical change, except
- magnetising of iron nail
- rusting of iron rod
- digestion of food
- souring of milk
Answer. 1. magnetising of iron nail
Question 3. Atomic number of an element gives
- the number of electrons in its atom
- the number of nucleons in its atom
- the weight of the atom of the element
- the total number of elementary particles in its atom
Answer. 1. the number of electrons in its atom
Question 4. Conversion of a substance directly from solid to vapour state is known as
- vapourization
- sublimation
- decomposition
- ionization
Answer. 3. decomposition
Question 5. Cooking oil can be converted into vegetable ghee by the process of
- hydrogenation
- distillation
- crystallization
- oxidation
Answer. 4. oxidation
Question 6. Colloids
- are true solutions
- are suspensions of one phase in another
- are two-phase systems
- contain only water soluble substances
Answer. 2. are suspensions of one phase in another
Question 7. Colloids are purified by
- peptization
- coagulation
- condensation
- dialysis
Answer. 1. peptization
Question 8. Distillation at reduced pressure is used for liquids which have
- high boiling points
- low boiling points
- high volatility
- decomposed before their boiling points
Answer. 4. decomposed before their boiling points
Question 9. Gases have
- a definite shape but not volume
- a definite volume and shape
- a definite volume but not shape
- neither definite volume nor shape
Answer. 4. neither definite volume nor shape
Question 10. Isotopes of an element
- are physically identical with each other
- are chemically identical with each other
- are not identical with each other
- have the same mass numbers
Answer. 2. are chemically identical with each other
Question 11. Milk is an example of
- sol
- gel
- emulsion
- suspension
Answer. 3. emulsion
Question 12. Of all the gases present in the air, which one of the following is the highest in percentage?
- Carbon dioxide
- Hydrogen
- Nitrogen
- Oxygen
Answer. 3. Nitrogen
Question 13. Of the following particles, the particle having the least mass is
- meson
- neutron
- electron
- proton
Answer. 3. electron
Question 14. The atomic weight of uranium is
- 237
- 238
- 226
- 242
Answer. 2. 238
Question 15. The charge on the electron is
- 1.6 × 10-16 C
- 1.5 × 10-16 C
- –1.6 × 10-19 C
- 1.6 × 1019 C
Answer. 3. –1.6 × 10-19 C
Question 16. The chemical name of table salt is
- potassium chloride
- sodium chloride
- calcium chloride
- sodium hyposulphate
Answer. 2. sodium chloride
Question 17. The difference between isotopes of an element is due to the presence of a different number of
- protons
- neutrons
- electrons
- photons
Answer. 2. neutrons
Question 18. The ejection of electrons when a metal surface is irradiated is called
- black body radiation
- photoelectric effect
- zeeman effect
- atomic spectrum
Answer. 2. photoelectric effect
Question 19. The major constituent of air is
- nitrogen
- carbon dioxide
- oxygen
- hydrogen
Answer. 1. nitrogen
Question 20. The mass number of a nucleus is
- always less than its atomic number
- the sum of the number of protons and neutrons present in the nucleus
- always more than the atomic weight
- a fraction
Answer. 2. the sum of the number of protons and neutrons present in the nucleus
Question 21. The mass of one Avogadro number of helium atom is
- 1.00 g
- 4.00 g
- 8.00 g
- 4 × 6.02 × 1023 g
Answer. 3. 8.00 g
Question 22. The maximum capacity of any orbital is
- 2
- 6
- 14
- Cannot be determined unless the principal quantum number is known
Answer. 2. 6
Question 23. The melting point of copper is
- 1,083°C
- 732°C
- 327°C
- 1,835°C
Answer. 1. 1,083°C
Question 24. The most abundant rare gas in the atmosphere is
- He
- Ne
- Ar
- Xe
Answer. 3. Ar
Question 25. The nuclear particles that are assumed to hold nucleons together are
- electrons
- positrons
- neutrons
- mesons
Answer. 4. mesons
Question 26. The nucleus of a hydrogen atom consists of
- one proton + one neutron
- one proton + two neutrons
- one neutron only
- one electron only
Answer. 3. one neutron only
Question 27. Tritium has an atomic number of
- 3
- 2
- 1
- 4
Answer. 1. 3
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Question 28. Which of the following has the same atomic number and atomic weight?
- Hydrogen
- Helium
- Oxygen
- Nitrogen
Answer. 2. Helium
Question 29. Which of the following is a chemical change?
- evaporation of water
- burning of candle
- glowing of an electric bulb
- liquefaction of air
Answer. 1. evaporation of water
Question 30. Which of the following is a mixture?
- gunpowder
- iron sulphate
- brass
- dry ice
Answer. 4. dry ice
Question 31. Which of the following is incorrect?
- Mercury: Hg
- Silver: Ag
- Sodium: Na
- Potassium: Ka
Answer. 2. Silver: Ag
Question 32. Which of the following is not a chemical action?
- Burning of coal
- Conversion of water into steam
- Digestion of food
- Burning of paper
Answer. 2. Conversion of water into steam
Question 33. A small quantity of a mixture of two days can be separated by
- fractional distillation
- paper chromatography
- sublimation
- steam distillation
Answer. 4. steam distillation
Question 34. Bohr model of an atom could not account for
- emission spectrum
- absorption spectrum
- line spectrum of hydrogen
- fine spectrum
Answer. 1. emission spectrum
Question 35. Camphor can easily be purified by the process of
- sublimation
- distillation
- crystallization
- sedimentation
Answer. 2. distillation
Question 36. Gunpowder is a mixture of
- sulphur, carbon and phosphorus
- sulphur, charcoal and nitre
- sulphur, charcoal and carbon
- carbon, nitrogen and chlorine
Answer. 3. sulphur, charcoal and carbon
Question 37. Match the following columns
List I List II
A. Mercury 1. Element
B. Oxygen 2. Compound
C. Water 3. Mixture
D. Air Codes 4. Metal
A B C D
1 2 3 4
4 3 2 1
4 1 2 3
4 2 3 1
Answer. 3. 4 1 2 3
Question 38. Blue colour of the sky is due to
- absorption of light by dust particles
- reflection of light by dust particles
- scattering of light by dust particles
- the presence of clouds which are a colloidal dispersion of water particles in air
Answer. 1. absorption of light by dust particles
Question 39. If NA is Avogadro‘s number, then number of electrons in 4.2 g of azide ions (N3–) is
- 2 NA
- 4.2 NA
- 1.6 NA
- 3.6 NA
Answer. 2. 4.2 NA
Question 40. The number of atoms present in 21.6 g of silver (atomic weight = 108) are same as the molecules in
- 1.8 g of H2O
- 12 moles of KMnO4
- 0.6 N H2SO4
- 4.6 g of C2H5OH
Answer. 1. 1.8 g of H2O
Question 41. 19.7 kg of gold was recovered from a smuggler. how many atoms of gold were recovered?
(Au = 197)
- 6.02 × 1025
- 6.02 × 1024
- 6.02 × 1023
- 6.02 × 1022
Answer. 1. 6.02 × 1025
Question 42. Butter is an example of
- gel
- emulsion
- sol
- foam
Answer. 3. sol
Question 43. An element M has an atomic number 9 and atomic mass 19. Its ion will be presented by
- M
- M2+
- M–
- M2-
Answer. 2. M2+
Question 44. Milk is
- fat dispersed in milk
- fat dispersed in water
- water dispersed in fat
- water dispersed in oil
Answer. 2. fat dispersed in water
Question 45. the formula of the compound is A2B5. The number of electrons in the outermost orbits of A and B respectively are
- 6 and 3
- 5 and 6
- 5 and 2
- 2 and 3
Answer. 4. 2 and 3
Question 46. Milk is a mixture of
- fats and water
- carbohydrates and water
- carbohydrates, fats and water
- carbohydrates, fats, proteins and water
Answer. 2. carbohydrates and water
Question 47. Swelling of a sprained foot is reduced by soaking in hot water containing a large amount of common salt. This is because of a phenomenon called
- osmosis
- plasmolysis
- electrolysis
- dialysis
Answer. 4. dialysis
Question 48. The percentage, by weight, of water in the human body is
- 20
- 40–45
- 5–10
- 70–75
Answer. 4. 70–75
Question 49. The so-called fourth state of matter refers to
- mercury
- LPG
- dry ice
- plasma
Answer. 3. dry ice
Question 50. Which of the following cannot be purified by sublimation?
- iodine
- camphor
- citric acid
- naphthalene
Answer. 2. camphor
Question 51. Which of the following gases in air unites with many metals?
- hydrogen
- oxygen
- helium
- carbon dioxide
Answer. 1. hydrogen
Question 52. Why does milk curdle?
- fermentation of lactose
- reaction of microbes
- overheating
- fungus growth
Answer. 3. overheating
Question 53. A fractionating column is a glass apparatus used to
- separate magnetic solids from nonmagnetic solids
- separate a mixture in water
- separate two or more liquids
- extract oils from vegetable matter
Answer. 1. separate magnetic solids from nonmagnetic solids
Question 54. In case of a chemical change, which of the following is generally affected?
- electron
- proton
- neutron
- nucleus
Answer. 1. electron
Question 55. In the natural ‘water cycle’, water gets purified by
- evaporation and condenzation
- sedimentation
- filtration
- distillation
Answer. 3. filtration
Question 56. Neutrons are obtained by
- bombardment of radium with a-particles
- bombardment of beryllium with a particles
- radioactive disintegration of uranium
- None of these
Answer. 2. bombardment of beryllium with a particles
Question 57. Radioactive isotope of hydrogen is
- Hydride ion
- Tritium
- Protium
- Deuterium
Answer. 3. Protium
Question 58. The British physicist who received the 1923 Nobel Prize in Physics for discovering the electron is
- John Dalton
- James Chadwick
- J J Thomson
- E Rutherford
Answer. 2. James Chadwick
Question 59. The number of electrons present in H+ is
- zero
- one
- two
- three
Answer. 3. two
Question 60. The smallest particle of a pure substance showing all the properties is
- always an atom
- always a molecule
- may be an atom or a molecule
- a proton
Answer. 2. always a molecule
Question 61. The total energy of an electron revolving round the nucleus is
- less than zero
- zero
- more than zero
- more than zero in some atoms and less than zero in other atoms
Answer. 1. less than zero
Question 62. When hydrogen nuclei trap neutrons, they become
- hydrogen atoms
- deuterons
- tritium atom
- beta rays
Answer. 2. deuterons
Question 63. Which of the following statements concerning an electron is false?
- It is a particle
- It has wave properties
- Its path is bent by a magnet
- It gives out energy while moving in orbit
Answer. 4. It gives out energy while moving in orbit
Question 64. Which of the following statements is true?
- The ‘free’ electron outside the atom can have only discrete energy, in accordance with the quantum theory
- The electron inside the atom can have a continuous range of energies
- The kinetic energy of a free electron outside the atom can have any value in a continuous range
- None of these
Answer. 3. The kinetic energy of a free electron outside the atom can have any value in a continuous range
Question 65. _________is the simplest form of matter.
- Liquid
- Solid
- Gas
- Plasma
Answer. 3. Gas
Question 66. A solution can be
- Dilute and concentrated
- Saturated and dilute
- Saturated and unsaturated
- Supersaturated and saturated
Answer. 2. Saturated and dilute
Question 67. Alpha rays are actually
- 1 protons 2 neutrons
- 2 protons 2 electrons
- 2 protons 2 neutrons
- 2 protons 1 neutrons
Answer. 3. 2 protons 2 neutrons
Question 68. Atomic weight of Ca is
- 20
- 40
- 45
- 80
Answer. 2. 40