Chemistry (Theory)
Class – XII
Time allowed: 3 hrs M.Marks: 70
General instructions:-
i. All questions are compulsory.
ii. Internal choices has been provided in some questions you have to attempt only one of the choice in such questions.
iii. Q.No 1 to 8 are very short answer type questions, carrying one mark each.
iv. Q. No. 9 to 18 are short answer type questions, carrying two mark each.
v. Q.No. 19 to 27 are also short answer questions, carrying three mark each.
vi. Q.No. 28 to 30 are long answer type questions, carrying five mark each.
vii. Use of calculators is not permitted. However you may use log tables, if necessary.
Q1. People living at high altitude generally suffer from anoxia , Explain.
Q2. Define limiting molar conductivity.
Q3. “A greater insight in to the energetic and mechanistic aspects of reactions”. Explain the above statement which was given by “Max Trautz” and William Lewis”.
Q4. Why glass is called super cooled liquid?
Q5. Why nitrogen is highly unreactive at room temperature?
Q6. Write the names of the monomers of nylon.
Q7. Write IUPAC name of: C6H5 NHCOCH3.
Q8. Write IUPAC name of the ionization isomer of: [Cr (NH3)5 Br] SO4.
Q9. Find the charge required for:
(i) Oxidation of 1 mol water (ii) Reduction of 1mol Fe2O3 into FeO .
Q10. What do you mean by activity and selectivity of catalysts?
Q11. Mention the factors which affect the rate of a chemical reaction.
Q12. What is osmosis? Can this process be reversed? What are the conditions required?
Q13. Write a short note on collision theory of chemical reactions.
Q14. What are reducing and non-reducing sugars? Give examples .
Q15. Account for the following :
(i) Alkaline medium inhibits the rusting of iron.
(ii)Iron does not rust even if zinc coating is broken in a galvanized iron pipe.
Q16. How the following conversions can be carried out?
(i) Toluene to benzyl alcohol
(ii) Ethanol to but-1-yne.
Q17. What is Lanthanoid Contraction? Mention two consequences of Lanthanoid contraction.
Q18. Distinguish chemically between:
a) phenol and ethanol
b) methanal and ethanal.
Q19. Al crystallizes in a cubic close packing structure (FCC) Its metallic radius is 125 pm .Find the edge length of the unit cell. How many unit cells are there in 1cm3 of Al ? How many atoms are there in 1cm3 of Al ?
Q20. Give the structures of
a) XeO3 b) H3PO4 c) PCl3
Q21. a) Write main postulates of werner,s co-ordination theory.
b) Draw the geometrical isomers of [Co(NH3)3(NO2)3]
Q22. Silver crystallizes in fcc lattice. If edge length of the cell is 4.77 x 10-8 Cm and density is 10.5 gm/cm3, calculate the atomic mass of Silver.
Q23. What are emulsions? What are their different types? Give one example of each type.
Q24. Write following name reactions:
(i) Swarts reaction
(ii) Sandmeyer reaction
(iii) Gatterman reaction
Q25. What are Tranquilizers? Give examples?
Q26. (a) What are the classes of neurologically active drugs? Write one example for each.
(b) What is the use of sodium benzoate in food?
Q27. i) Explain the following with respect to protein-
a) Native state of protein
b) Peptide linkage
ii) Two strands of DNA are not identical but complimentary to each other. Explain this statement.
Q28. a) Write the reaction involved at each electrode in H2-O2 fuel cell.
b) Give one similarity and one difference between fuel cell and other primary cells.
c) Give advantages of fuel cells.
Q29. a) State Kohlrausch law of independent migration of ions.
b) Write the reaction involved at each electrode in mercury cell / dry cell.
c) Calculate the cell potential at 298K for the reaction
Zn+Sn4+ → Zn2+ +Sn2+
(1.5M) 0.5M) (2M)
E0Zn2+/Zn= - 0.76V E0Sn4+/Sn2+= 0.13V
Q30. What are the Colligative properties? Explain any one of them. Show that elevation in boiling point is a Colligative property.
OR
Acetaldehyde undergoes a reaction to form a product which exhibits properties of aldehydes and alcohols.
(i) Name the reaction and give equation.
(ii) Write the structural formula of the product formed.
(iii) What are the reagents other than acetaldehyde required for the reaction to take place?
(iv) Why acetaldehyde gives this reaction?
(v) What happens if acetaldehyde is reacted with acetone?
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