CBSE class XII Chemistry Important questions 2008


Q. 1. Draw the resonating structures of

  1. NO
  2. NO2
  3. N2O
  4. N2O3
  5. N2O4
  6. N2O5.
  7. O3.

Also draw the structures of each clearly depicting the bond parameters.

Q. 2. Draw the resonance structures of SO2.

Q. 3. Draw the structures of

  1. NH3
  2. HNO3
  3. White phosphorus
  4. Red phosphorus
  5. PCl3
  6. PCl5
  7. Phosphoric acid
  8. Phosphorus acid
  9. Hypo phosphorus acid
  10. Pyro phosphoric acid
  11. cyclic tri meta phosphoric acid
  12. Poly meta phosphoric acid.
  13. S8
  14. S6
  15. Sulphuric acid
  16. sulphurus acid
  17. Peroxo di sulphuric acid
  18. Pyro sulphuric acid (oleum)
  19. HOCl
  20. HClO2
  21. HClO3
  22. HClO4
  23. BrF3
  24. IF5
  25. IF7
  26. IF4- aa) SF4 bb) SF6 cc) XeOF4 dd) BrO3- ee) XeF2 ff) XeF4 gg) XeF6 hh) XeOF4 ii) XeO3

Q. 4. Give the formula and structure of noble gas species which is iso structural with

  1. ICl4-
  2. IBr2-
  3. IF6-
  4. BrO3-

Q. 5. Why does nitrogen shows anomalous behavior? Give examples to show the anomalous behavior of nitrogen.

Q. 6. Why does oxygen shows anomalous behavior? Give examples to show the anomalous behavior of oxygen.

Q. 7. Why does fluorine shows anomalous behavior? Give examples to show the anomalous behavior of fluorine.

Q. 8. Describe the method of preparation of

  1. NH3 by Haber procssssess
  2. HNO3 by Ostwald process
  3. H2SO4 by contact process.

Give three uses of each.

Q. 9. Explain brown ring test for nitrate with suitable equations.

Q. 10. What is disproportionation reaction? Give equation of the reactions involved in the disproportionation of

  1. HNO2
  2. Se2Cl2
  3. H3PO2

Q. 11. How is ozone estimated quantitatively?

Q. 12. Give two uses each of

  1. N2
  2. PH3
  3. O2
  4. Ozone
  5. SO2
  6. Cl2
  7. ClO2
  8. BrO3
  9. I2O5
  10. Cl2 k) HCl
  11. ClF3
  12. He
  13. Ne
  14. Ar
  15. Kr
  16. Xe

Q. 13. How is NH3(aq) used in salt analysis to determine the presence of

  1. Fe3+
  2. Zn2+
  3. Ag+

in salt analysis. Write the equations of the reactions involved.

Q. 14. How is the presence of SO2 detected?

Q. 15. What is aqua regia? How does it dissolve noble metals like Au and Pt? Write the equations of the reactions involved.

Q. 16. Give differences between white phosphorus and red phosphorus.

Q. 17. How is

  1. N2
  2. O2
  3. Cl2 prepared in the laboratory? Write the equations of the reactions involved.

Q. 18. How is

  1. N2
  2. O2
  3. Cl2 manufactured in the industry? Write the equations of the reactions involved in the manufacture of Cl2.

Q. 19. How is ammonia prepared in laboratory? Write the equation of the reaction involved.

Q. 20. How is HNO3 prepared in laboratory? Write the equation of the reaction involved.

Q. 21. How is phosphine prepared from

  1. Calcium phosphide
  2. White phosphorus.

Write the equations of the reactions involved.

Q. 22. How is PCl5 prepared from

  1. Cl2
  2. SO2Cl2?

Write the equations of the reactions involved

Q. 23. How is PCl3 prepared from

  1. Cl2
  2. SOCl2?

Write the equations of the reactions involved

Q. 24. How is HCl prepared from NaCl? Write the equations of the reactions involved

Q. 25. Write the chemical formula of

  1. Chile saltpetre
  2. Indian saltpetre
  3. Fluorapatite
  4. Gypsum salt
  5. Epsom salt
  6. Baryte
  7. Galena
  8. Zinc blende
  9. Copper pyrite
  10. Florospar
  11. cryolite
  12. Fluoroapatite
  13. carnalite.
  14. Tear gas
  15. mustard gas
  16. Phosgene

Q. 26. With what neutral molecule ClO- is iso electronic? Is that molecule a lewis base?

Q. 27. Compare the chemistry of Sulphur.What is the transition temperature of Sulphur.

Q. 28. How is phosphine purified? Write the equations of the reactions involved.

 

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