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CBSE Guess > Papers > Important Questions > Class XII > 2007 > Chemistry > P Block Elements

P Block Elements

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  1. Name the elements present in boranes.
  2. Write two uses of pyrophoric allow.
  3. How is orthoboric acid related to metaboric acid?
  4. What is inert pair effect.
  5. Mention an important application of silicones.
  6. Write one use of elemental selenium.
  7. Molecular nitrogen is not reactive. Explain.
  8. Mention an important property of hydrazine.
  9. Write the structure of pyrophosphoric acid.
  10. Water is liquid where as Hydrogen sulphide is a gas at room temperature. why.


  1. Explain why Boron tri chloride is monomer but anhydrous Aluminium tri chloride is dimeric.
  2. What is meant by 'catenation' How does the catenation tendency for elemnts of group 14 vary.
  3. How is that silicon atoms can have coordination number more than four but carbon atoms can not.
  4. What is intert pair effect. Discuss the oxidation states of Group 13 elements in relation to this effect.
  5. Explain why phosphorous forms penta halide whereas nitrogen cannot.


  1. Give the comparative account of the chemistry of carbon and silicon with regard to their:
    [i] property of catenation
    [ii] stability of hydrides and oxides
  2. Account for the following:
    [i] Ammonia has higher boiling point than phosphine
    [ii] Trimethyl ammine is pyramidal and trisilyl ammine is planar.
    [iii] Ammonia is stronger base than phosphine.
  3. Describe the following about halogen family:
    [i] Oxidising power
    [ii] Relative strength of their hydrides
    [iii] Oxyacids and their related oxidising ability
  4. Give reason for the following observations.
    [i] Noble gases are mostly chemicallly inert
    [ii] Nitrogen does not form pentahalide
    [iii] Bismuth is a strong oxidising agent in pentavalent state
  5. [i] Discuss two similar and two dissimilar properties from the chemistry of nitrogen and that of phosphorous.
    [ii] State the reason for the occurrence of diagonal relationship in the periodic table


  1. [A] What are silicones.
    1. Oxidation states of tin and lead
    2. Structures of oxides of nitrogen and phosphorus
    3. Electron affinities of chlorine and fluorine
    4. Maximum covalency of oxygen and sulphur
  1. Atomic Structure and Chemical Bonding
  2. Solid State
  3. Solutions
  4. Thermodynamics
  5. Electrochemistry
  6. Chemical Kinetics
  7. P Block Elements
  8. D and F Block Elements
  9. Nuclear Chemistry
  10. Stereo Chemistry
  11. Organic Functional Group I
  12. Organic Functional Group II and III
  13. Surface Chemistry
  14. Chemistry In Every Day Life
  15. Polymers
  16. Practice Paper No.1
  17. Practice Paper No.2
  18. Practice Paper No.3
  19. Practice Paper No.4


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