Chemistry MCQ Question and Answer

1.What happens when a chemical bond is formed?

  • AEnergy is always absorbed
  • BEnergy in always released
  • CMore energy is released than is absorbed
  • DEnergy is neither released nor absorbed
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Correct Answer : (A)

Energy is always absorbed

Explanation:

2.“All the four quantum numbers of two electrons in an atom are not the same.” It is the law of – 

  • AHund’s
  • BExclusion principle of pauli
  • CUncertainty principle of Hiesenberg
  • DAvogadro’s law
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Correct Answer : (B)

Exclusion principle of pauli

Explanation:

3.The atomic number of carbon is 6 and its atomic mass is 12. How many protons are there in the nucleus of carbon?

  • A6
  • B12
  • C18
  • DZero
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Correct Answer : (A)

6

Explanation:

4.Nucleus of an atom consists of

  • AProton
  • BNeutron
  • CProton and neutron
  • DElectron, proton and neutron
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Correct Answer : (C)

Proton and neutron

Explanation:

5.Isobars are lines joining places having equal

  • ARainfall
  • BPressure
  • CPopulation
  • DHeight above sea – level
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Correct Answer : (B)

Pressure

Explanation:

6.What is the element that is in the highest percentage in the composition of the earth?

  • ASilicon
  • BOxygen
  • CMagnesium
  • DIron
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Correct Answer : (B)

Oxygen

Explanation:

7.Milk is a natural

  • ASolution
  • BEmulsion
  • CMixture
  • DSuspension
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Correct Answer : (B)

Emulsion

Explanation:

8.Sea water can be purified by the process of

  • ADistillation
  • BEvaporation
  • CFiltration
  • DFractional distillation
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Correct Answer : (A)

Distillation

Explanation:

9.The residue left after extracting juice from sugar-beet and sugarcane is called

  • AMolasses
  • BBagasse
  • CWhey
  • DBiomass
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Correct Answer : (B)

Bagasse

Explanation:

10.The process of removing calcium and magnesium from hard water is known as

  • ASedimentation
  • BFiltration
  • CFlocculation
  • DWater softening
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Correct Answer : (D)

Water softening

Explanation:

11.The national Chemical Laboratory (India) is located in

  • AMumbai
  • BBangaluru
  • CHyderabad
  • DPune
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Correct Answer : (D)

Pune

Explanation:

12.Which of the following is not a nucleon?

  • AProton
  • BNeutron
  • CElectron
  • DPositron
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Correct Answer : (D)

Positron

Explanation:

13.What particles move around the nucleus of an atom and are negatively charged?

  • AElectrons
  • BProtons
  • CPositrons
  • DNeutrons
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Correct Answer : (A)

Electrons

Explanation:

14.The number of neutrons present in an element having mass number 226 and atomic number 88 is

  • A88
  • B138
  • C314
  • D50
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Correct Answer : (B)

138

Explanation:

15.An atom of an element has atomic number 17 and mass number 36. The number of neutrons in its nucleus is

  • A17
  • B19
  • C36
  • D53
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Correct Answer : (B)

19

Explanation:

16.Select the one which is not a mixture

  • AAir
  • BGasoline
  • CLPG
  • DDistilled water
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Correct Answer : (D)

Distilled water

Explanation:

17.The total energy of revolving electron in an atom

  • ACannot be negative
  • BCan have any value above zero
  • CCan never be positive
  • DWill always be positive
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Correct Answer : (C)

Can never be positive

Explanation:

18.Conduction band electrons have more mobility than holes because they

  • AAre lighter
  • BExperience collision less frequently
  • CHave negative charge
  • DNeed less energy to move them
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Correct Answer : (B)

Experience collision less frequently

Explanation:

19.The mass number of a nucleus is

  • AAlways less than its atomic number
  • BAlways more than its atomic number
  • CAlways equal to its atomic number
  • DSometimes more and sometimes equal to its atomic number
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Correct Answer : (D)

Sometimes more and sometimes equal to its atomic number

Explanation:

20.The chemical behaviour of an atom depends upon

  • AThe number of protons in its nucleus
  • BThe number of neutrons in its nucleus
  • CThe number of electrons orbiting around the nucleus
  • DThe number of nucleons in the nucleus
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Correct Answer : (C)

The number of electrons orbiting around the nucleus

Explanation: