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12th Standard Chemistry p Block Elements II 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. Which is true regarding nitrogen?

    (a)

    least electronegative element

    (b)

    has low ionisation enthalpy than oxygen

    (c)

    d- orbitals available

    (d)

    ability to form pπ-pπ bonds with itself

  2. Solid (A) reacts with strong aqueous NaOH liberating a foul smelling gas(B) which spontaneously burn in air giving smoky rings. A and B are respectively

    (a)

    P4(red) and PH3

    (b)

    P4(white) and PH3

    (c)

    S8 and H2S

    (d)

    P4(white) and H2S

  3. On hydrolysis, PCl3 gives

    (a)

    H3PO3

    (b)

    PH3

    (c)

    H3PO4

    (d)

    POCl3

  4. The basicity of pyrophosphorous acid ( H4P2O5) is

    (a)

    4

    (b)

    2

    (c)

    3

    (d)

    5

  5. Assertion : bond dissociation energy of fluorine is greater than chlorine gas
    Reason: chlorine has more electronic repulsion than fluorine.
    Codes:
    (a) Both assertion and reason are true and reason is the correct explanation of assertion.
    (b) Both assertion and reason are true but reason is not the correct explanation of assertion
    (c) Assertion is true but reason is false
    (d) Both assertion and reason are false

    (a)

    Both assertion and reason are true and reason is the correct explanation of assertion.

    (b)

    Both assertion and reason are true but reason is not the correct explanation of assertion

    (c)

    Assertion is true but reason is false

    (d)

    Both assertion and reason are false

  6. Most easily liquefiable gas is

    (a)

    Ar

    (b)

    Ne

    (c)

    He

    (d)

    Kr

  7. Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?

    (a)

    Br2 > I2 > F2 > Cl2

    (b)

    F2 > Cl2 > Br2 > l2

    (c)

    I2 > Br2 > Cl2 > F2

    (d)

    Cl2 > Br2 > F2 > I2

  8. When copper is heated with conc HNO3 it produces

    (a)

    Cu(NO3)2 , NO and NO2

    (b)

    Cu(NO3)2 and N2O

    (c)

    Cu(NO3)2 and NO2

    (d)

    Cu(NO3)2 and NO

  9. Catenation property of group 15 elements, follow the order

    (a)

    N < P < As < Sb < Bi

    (b)

    P >> N > As > Sb > Bi

    (c)

    P < N < As < Sb < Bi

    (d)

    N>> P > As > Sb > Bi

  10. Which is dibasic?

    (a)

    Orthophosphoric acid

    (b)

    Pyrophosphoric acid

    (c)

    Orthophosphorus acid

    (d)

    Hypophosphorus acid

  11. Allotrope of sulphur which shows paramagnetic behaviour

    (a)

    S8- Rhombic

    (b)

    S8- Monoclinic

    (c)

    S2- In vapour phase

    (d)

    Not possible

  12. Pick the wrong one among the following

    (a)

    F2 - Yellow

    (b)

    Br2 - Red

    (c)

    Cl2 - Colourless

    (d)

    I2- Violet

  13. When Copper is heated with cone HNO3 it produces

    (a)

    Cu (NO3)2 and N20

    (b)

    Cu (NO3)2 and NO2

    (c)

    Cu (NO3)2 and NO

    (d)

    Cu (NO3)2 NO and N2O

  14. Oxalic acid on heating with cone H2SO4 gives

    (a)

    CO only

    (b)

    CO2 only

    (c)

    CO2+ H20

    (d)

    CO + CO2 + H2O

  15. Which among the following ion is not formed?

    (a)

    F3-

    (b)

    C13-

    (c)

    Br3-

    (d)

    I3-

  16. The incorrect statement among the following is_________

    (a)

    Reducing character of hydrides of group 15 increases down the group

    (b)

    Basicity of hydrides of group 15 increases down the group

    (c)

    NCl5 does not exist

    (d)

    Phosphorus and arsenic can form P\(\pi \)-drt bond but not nitrogen

  17. Maximum covalent character is shown by__________

    (a)

    PCl3

    (b)

    NCl3

    (c)

    AsCl3

    (d)

    SbCl3

  18. Repeated use of which one of the following fertilizers would increase the activity of the soil_______

    (a)

    Ammonium sulphate

    (b)

    Superphosphate of lime

    (c)

    Urea

    (d)

    Potassium nitrate

  19. Oxidation states of P in H4P2O5, H4P2O6, H4P2O7 are respectively _________

    (a)

    +3, +4, +5

    (b)

    +3, +5, +4

    (c)

    +5,+3,+4

    (d)

    +5,+4,+3

  20. Helium is used in balloons in the place of, hydrogen because it is________

    (a)

    incombustible

    (b)

    radioactive and detected easily

    (c)

    lighter than hydrogen

    (d)

    both (a) and(c)

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