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12th Standard Chemistry p Block Elements I English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

12th Standard

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Chemistry

Time : 00:20:00 Hrs
Total Marks : 20
    Answer all the questions
    20 x 1 = 20
  1. Boric acid is an acid because its molecule________.

    (a)

    contains replaceable H+ ion

    (b)

    gives up a proton

    (c)

    combines with proton to form water molecule

    (d)

    accepts OH- from water, releasing proton.

  2. Which of the following metals has the largest abundance in the earth’s crust?

    (a)

    Aluminium

    (b)

    Calcium

    (c)

    Magnesium

    (d)

    Sodium

  3. In diborane, the number of electrons that accounts for banana bonds is ________.

    (a)

    six

    (b)

    two

    (c)

    four

    (d)

    three

  4. Oxidation state of carbon in its hydrides _______.

    (a)

    +4

    (b)

    -4

    (c)

    +3

    (d)

    +2

  5. The repeating unit in silicone is_______.

    (a)

    SiO2

    (b)

    (c)

    (d)

  6. The geometry at which carbon atom in diamond are bonded to each other is _______.

    (a)

    Tetrahedral

    (b)

    hexagonal

    (c)

    Octahedral

    (d)

    none of these

  7. AlF3 is soluble in HF only in the presence of KF. It is due to the formation of _________.

    (a)

    K3[AIF3H3]

    (b)

    K3[AiF6]

    (c)

    AIH3

    (d)

    K[AIF3H]

  8. Thermodynamically the most stable form of carbon is________.

    (a)

    Diamond

    (b)

    graphite

    (c)

    Fullerene

    (d)

    none of these

  9. The stability of +1 oxidation state increases in the sequence ________.

    (a)

    Al < Ga < In < Tl

    (b)

    Tl < In < Ga < Al

    (c)

    In < Tl < Ga < Al

    (d)

    Ga< In < Al < Tl

  10. Select the incorrect statement regarding B2H6.

    (a)

    It contains B-B ionic bond

    (b)

    Each boron is Sp3 hybridised

    (c)

    It has two types of hydrogen bonds

    (d)

    it is used as a reducing agent

  11. Which one of the following compounds has similar structure to that of graphite?

    (a)

    Boron nitride

    (b)

    Boron Carbide

    (c)

    Aluminium Carbide

    (d)

    Aluminium Oxide

  12. Graphite has _______.

    (a)

    2-d sheet structure

    (b)

    Vander waals force between successive layers of carbon sheets

    (c)

    Sp2 hybridised carbon linked with other three carbon atoms in hexagonal planar structure

    (d)

    all the above

  13. Which one is correct statement for zeolite?

    (a)

    Zeolites are aluminosilicates having three dimensional framework

    (b)

    Hydrate zeolites are used as ion exchangers in hardening of soft water

    (c)

    Zeolites are alumino silicates

    (d)

    all the above

  14. Identify the electron - deficient species

    (a)

    (BH3)2

    (b)

    (SiH3)2

    (c)

    PH3

    (d)

    (CH3)2

  15. Boron compounds behave as Lewis acid, because of their _______.

    (a)

    ionisation property

    (b)

    acidic nature

    (c)

    covalent nature

    (d)

    electron deficient nature

  16. On moving down the group 13, density ______

    (a)

    decreases

    (b)

    increases

    (c)

    First decreases then increases

    (d)

    remains same

  17. Oxidation state exhibited by group 13 elements is ______

    (a)

    +1, +2 and +3

    (b)

    +1 and +3

    (c)

    +1 and +4

    (d)

    +2 +3 and +4

  18. Aluminium is used for making alloys because of its _____

    (a)

    resistance to corrosion

    (b)

    poor conductivity

    (c)

    heaviness

    (d)

    all of these

  19. Allotropy is due to ______.

    (a)

    difference in chemical properties

    (b)

    difference in the number of atoms in the molecules

    (c)

    difference in the arrangement of atoms in the molecules in the crystal

    (d)

    None of these

  20. Silicones are ______.

    (a)

    ortho silicates

    (b)

    water repellent thermal insulators

    (c)

    both (a) and (b)

    (d)

    None of these

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