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CBSE Guess > Papers > Important Questions > Class XII > 2010 > Chemistry > Chemistry By Mr. Mahendra Kalra

CBSE CLASS XII

Q. 1. While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?

Q. 2. Low level of noradrenaline is the cause of depression. What type of drugs are needed to cure this problem? Name two drugs.

Q. 3. Name the members of the lanthanoid series which exhibit +4 oxidation states and those which exhibit +2 oxidation states.

Q. 4. For the reaction A -> B the rate becomes 27 times when the concentration of A is increased 3 times. What is the order of reaction

Q. 5. What is meant by the term ‘broad spectrum antibiotics’? Explain.

Q. 6. Explain the term copolymerisation and give one example.

Q. 7. Write the free radical mechanism for the polymerisation of ethene.

Q. 8. Write the monomers used for .

  1. PVC
  2. Teflon
  3. Bakelite

Q. 9. Define the following

  1. Peptide linkage
  2. Primary structure
  3. glycosidic linkage.

Q. 10. What is the difference between a nucleoside and a nucleotide?

Q. 11. Account for the following:

  1. Of the d4 species, Cr2+ is strongly reducing while Mn+3 is strongly oxidising.
  2. Co2+ is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
  3. The d1 configuration is very unstable in ions.

Q. 12. Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: [Co(C2O3)3]3– (iv) [CoF6]3–

Q. 13. Give evidence that [Co(NH3)5Cl]SO4 and [Co(NH3)5SO4]Cl are ionisation isomers.

Q. 14. What do you understand by activation of adsorbent? How is it achieved?Or
Calculate the efficiency of packing in case of a metal crystal for face-centred cubic

Q. 15. What role does adsorption play in heterogeneous catalysis? Or
How will you distinguish between the Hexagonal close-packing and cubic close-packing?

Q. 16. A 5% solution (by mass) of cane sugar in water has freezing point of 271K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.

Q. 17. State Henry’s law and mention some important applications?

Q. 18. Resistance of conductivity cell filled with 0.1molL-1 KCl solution is 100 ohm. If the resistance of the same cell when filled with 0.02molL-1 KCl solution is 520 ohm. Calculate the conductivity & molar conductivity of 0.02molL-1 KCl solution. The conductivity of 0.1 molL-1 solution of KCl is 1.29Sm-1.

Q. 19. During nuclear explosion, one of the products is 90Sr with half-life of 28.1 years. If 1 u of 90Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years if it is not lost metabolically.

Paper By Mr. Mahendra Kalra
Email Id :kalra1977@rediffmail.com
Ph No.: 9460472649