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12th Standard Chemistry English Medium P - Block Elements - II Reduced Syllabus Important Questions With Answer Key 2021

12th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 100

    Multiple Choice Questions

    15 x 1 = 15
  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. The molarity of given orthophosphoric acid solution is 2M. its normality is

    (a)

    6N

    (b)

    4N

    (c)

    2N

    (d)

    none of these

  3. The correct order of the thermal stability of hydrogen halide is

    (a)

    HI > HBr > HCl > HF

    (b)

    HF > HCl > HBr > HI

    (c)

    HCl > HF > HBr > HI

    (d)

    HI > HCl > HF > HBr

  4. Which one of the following compounds is not formed?

    (a)

    XeOF4

    (b)

    XeO3

    (c)

    XeF2

    (d)

    NeF2

  5. 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

  6. Among the following the correct order of acidity is

    (a)

    HClO2 < HClO < HClO3 < HClO4

    (b)

    HClO4 < HClO2 < HClO < HClO3

    (c)

    HClO3 < HClO4 < HClO2 < HClO

    (d)

    HClO < HClO2 < HClO3 < HClO4

  7. Which is dibasic?

    (a)

    Orthophosphoric acid

    (b)

    Pyrophosphoric acid

    (c)

    Orthophosphorus acid

    (d)

    Hypophosphorus acid

  8. The hybridisation and shape of SF6 is respectively?

    (a)

    sp3d2,square planar

    (b)

    sp3d2,octahedral

    (c)

    sp3d see-saw

    (d)

    sp3d,trigonal bipyramindal

  9. Allotrope of sulphur which shows paramagnetic behaviour

    (a)

    S8- Rhombic

    (b)

    S8- Monoclinic

    (c)

    S2- In vapour phase

    (d)

    Not possible

  10. Least volatile hydrogen halide is

    (a)

    HF

    (b)

    HCI

    (c)

    HBr

    (d)

    HI

  11. Oxalic acid on heating with cone H2SO4 gives

    (a)

    CO only

    (b)

    CO2 only

    (c)

    CO2+ H20

    (d)

    CO + CO2 + H2O

  12. Which one of the following orders is not in accordance with the property stated against it?

    (a)

    F2> CI2> Br2> I2:Bond dissociation energy

    (b)

    HI > HBr> HCI > HF : Acidic property in water

    (c)

    F2> Cl2> Br2> l2: Oxidising power

    (d)

    F2> Cl2> Br2> l2: Electronegativity

  13. The incorrect statement regarding structure of ozone is______

    (a)

    Bond angle is less than 120°

    (b)

    It is linear

    (c)

    The two oxygen-oxygen bond length in ozone are identical

    (d)

    Both (b) and (c).

  14. Maximum covalent character is shown by__________

    (a)

    PCl3

    (b)

    NCl3

    (c)

    AsCl3

    (d)

    SbCl3

  15. The high reactivity of fluorine is due to_________

    (a)

    high ionisation energy

    (b)

    low bond dissociation energy

    (c)

    low electron affinity

    (d)

    high electro negativity

  16. 2 Marks

    10 x 2 = 20
  17. Explain why fluorine always exhibit an oxidation state of -1?

  18. What are interhalogen compounds? Give examples.

  19. Give the uses of helium.

  20. What is the hybridisation of iodine in IF7? Give its structure?

  21. Give two uses of nitrogen

  22. Give two uses of nitric acid

  23. What is phosphoresencer?

  24. Discuss the oxidising power of fluorine

  25. (i) Give correct order of boiling point of hydride of group 17.
    (ii) Fluorine exhibits only -1 oxidation state whereas other halogens show +1, +3, +5 and +7 oxidation state also Explain.

  26. Arrange the following as indicated below:
    (i) F2' Cl2, Br2, I2 - increasing bond dissociation enthalpy.
    (ii) HF, HCI, HBr, HI - increasing acidic strength.

  27. 3 Marks

    10 x 3 = 30
  28. How will you prepare chlorine in the laboratory?

  29. Give a reason to support that sulphuric acid is a dehydrating agent.

  30. Write the molecular formula and structural formula for the following molecules.
    a) Nitric acid
    b) dinitrogen pentoxide
    c) phosphoric acid
    d) phosphine

  31. Give the uses of argon.

  32. What is Haber's process? (or) How is ammonia synthesized by Haber's process?

  33. Name a reaction for the estimation of Ozone.

  34. Why do noble gases form compounds with fluorine and oxygen only?

  35. Out of H2O and H2S which one has higher bond angle and why?

  36. Why CIF 3 exists but FCl3 does not exist - Give reason.

  37. Complete the following reactions
    (l) Cl2+ H2O\(\longrightarrow \)?
    (ii) XeF6 + 2H2\(\longrightarrow \) ?
    (Iii) XeF6 + 2H2O\(\longrightarrow \)?

  38. 5 Marks

    7 x 5 = 35
  39. Suggest a reason why HF is a weak acid, whereas binary acids of the all other halogens are strong acids.

  40. What type of hybridisation occur in
    a) BrF5
    b) BrF3

  41. Mention the uses of helium

  42. Why is dioxygen a gas but sulphur a solid?

  43. An amorphous solid (A) burns in air to form a gas (B)which turns lime water milky. The gas is also produced as a byproduct during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO4 solution and reduces Fe3+ to Fe2+. Identify the solid 'A' and the gas 'B' and write the reactions involved.

  44. An element A occupies group number IS and period number 3, exhibits allotropy and it is tetra atomic. A reacts with caustic soda to give B which is having rotten fish odour. A reacts with chlorine to give C which has a pungent odour Identify A, Band C. Write the reactions.

  45. An element A occupies group number 15 and period number 3, reacts with chlorine to give compound B. The compound B on hydrolysis gives a dibasic acid C. The compound C on heating undergoes auto oxidation and reduction to give a tribasic acid D. Identify the elements A, compounds B, C and D. Write the reactions

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