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12th Standard Chemistry p Block Elements I English Medium Free Online Test One Mark Questions 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. An aqueous solution of borax is________.

    (a)

    neutral

    (b)

    acidic

    (c)

    basic

    (d)

    amphoteric

  2. Which among the following is not a borane?

    (a)

    B2H6

    (b)

    B3H6

    (c)

    B4H10

    (d)

    none of these

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

    (a)

    six

    (b)

    two

    (c)

    four

    (d)

    three

  4. Carbon atoms in fullerene with formula C60 have _______hybridisation.

    (a)

    sp3 hybridised

    (b)

    sp hybridised

    (c)

    sp2 hybridised

    (d)

    partially sp2 and partially sp3 hybridised

  5. The basic structural unit of silicates is _______.

    (a)

    \(\left( SiO_{ 3 } \right) ^{ 2- }\)

    (b)

    \(\left( SiO_{ 4 } \right) ^{ 2- }\)

    (c)

    \(\left( Sio \right) ^{ - }\)

    (d)

    \(\left( SiO_{ 4 } \right) ^{ 4- }\)

  6. Which of these is not a monomer for a high molecular mass silicone polymer?

    (a)

    Me3SiCl

    (b)

    PhSiCl3

    (c)

    MeSiCl3

    (d)

    Me2SiCl2

  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. Duralumin is an alloy of ______.

    (a)

    Cu,Mn

    (b)

    Cu,Al,Mg

    (c)

    Al,Mn

    (d)

    Al,Cu,Mn,Mg

  9. The compound that is used in nuclear reactors as protective shields and control rods is _________.

    (a)

    Metal borides

    (b)

    metal oxides

    (c)

    Metal carbonates

    (d)

    metal carbide

  10. Lewis acid character of boron trihalides is as a follows _______.

    (a)

    BF3 > BCl3 > BBr3 > BI3

    (b)

    BCI> BF3 > BBr3 > BI3

    (c)

    BI3 > BBr3 > BCl3 > BF3

    (d)

    BI3 > BF3 > BCl3 > BBr3

  11. The stability of +1 oxidation state among Al, Ga, In and Tl increases in sequence _______.

    (a)

    TI < In < Ga < Al

    (b)

    In < TI < Ga < Al

    (c)

    Ga < In < Al < TI

    (d)

    Al < Ga < In < TI

  12. Chemical formula of phosgene is_______.

    (a)

    COCl2

    (b)

    CaOCl2

    (c)

    CaCO3

    (d)

    COCI

  13. SiO44- ion has ____ geometry.

    (a)

    Triangular

    (b)

    Tetrahedral

    (c)

    Linear

    (d)

    Pentagonal bipyramidal

  14. Which of the following oxide is amphoteric?

    (a)

    SiO2

    (b)

    CO2

    (c)

    SnO2

    (d)

    CaO

  15. Which of the following statements about H3BO3 is not correct?

    (a)

    It has a layer structure in which planar BO3 units are joined by H-bonds

    (b)

    It is a strong tribasic acid

    (c)

    It is prepared by acidifying an aqueous solution of borax

    (d)

    It does not act as proton donor but acts as lewis acid by accepting hydroxyl ion

  16. In graphite electrons are _______.

    (a)

    localised on each C-atom

    (b)

    localised on every third C-atom

    (c)

    delocalised within the layer

    (d)

    present in anti-bonding orbital

  17. Elements of group 13 mainly form covalent compounds because ______

    (a)

    small size

    (b)

    electro negativity values are high

    (c)

    ionization energy is very high

    (d)

    both (a) and (c)

  18. All elements except carbon have the tendency to show maximum covalency of six ______

    (a)

    due to presence of vacant d-orbitals

    (b)

    due to absence of vacant d-orbitals

    (c)

    due to presence of partially filled d-orbitals

    (d)

    due to presence of completely filled d-orbitals

  19. The silicates which contain discrete tetrahedral units are _______.

    (a)

    ortho silicates

    (b)

    sheet silicates

    (c)

    pyrosilicates

    (d)

    three dimensional silicates

  20. Borax is _______.

    (a)

    Na2[B4O5(OH)4).8H2O

    (b)

    Na2[B4O5(OH)6).7H2O

    (c)

    Na2[B4O3(OH)8].6H2O

    (d)

    Na2[B4O2(OH)10).5H2O

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