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12th Chemistry Practice paper-01

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CHEMISTRY Class II PreUni Plus 2016-2017 Practice Paper - 01 Max. Marks Duration Date 70 3 hours 15 minutes 25-01-2017 Instructions 1. The questions paper has four parts: A, B, C and D. All parts are compulsory. 2. Write balanced chemical equations and draw labeled diagrams wherever required. 3. Use log tables and the simple calculator if necessary (Use of scientific calculators is not allowed). PART - A I. Answer the following questions (one mark each) [10 1 = 10] 1. What is the value of van t Hoff factor for a dilute solution of K2SO4 in water? (Assume complete ionization) 2. Mention the type of solution formed by ornamental gold. 3. When zinc is dipped in H2SO4, H2 is evolved but when Ag is dipped H2 is not evolved. Why? 4. Given : A B C , follows zero order kinetics. Write the rate equation (Given : order with respect to A is 1) 5. Between physisorption and chemisorption, which one has higher enthalpy of adsorption? 6. Name the refining process used for the purification of silicon. 7. Noble gases have very low boiling points. Why? 8. Write the IUPAC name of H CH3 H H H Br 9. Mention the hybridized state of carbonyl carbon atom. 10. Which vitamin deficiency causes pernicious anaemia? PART - B II. Answer any FIVE of the following questions (two marks each) [5 2 = 10] 11. Calculate the number of particles (atoms) per unit cell in a BCC crystal lattice. 12. Write the anodic and cathodic reactions in a lead acid battery, when it is discharged. 13. Show that for a first order reaction, time required for completion of 99.9% is 10 times the half life of the reaction. 14. What is Lanthanoid contraction? Write its consequences. 15. Complete the following reactions: Cu (i) R CH 2 OH 573K H (ii) CH 3 CH CH 2 H 2 O 16. Explain Clemmensen reduction with an example. 2P1617CPP1 1 17. Mention the role of following chemicals in food: (i) Butylated hydroxy anisole (BHA) (ii) Sucralose 18. What are broad spectrum antibiotics? Write an example. PART - C III. Answer any FIVE of the following questions (three marks each) [5 3 = 15] 19. Draw labeled diagram of Hall-Heroult electrolytic cell for the extraction of aluminium. Write the anode and cathode reactions. 20. Write the balanced chemical equation with conditions involved in manufacture of nitric acid by Ostwald s process. 21. Complete the following equations: (i) Br2 5F2 [1] (excess) (ii) Cu 2H 2SO 4 [1] (iii) PbS 4O3 [1] 22. (a) How is chlorine prepared in the laboratory using KMnO4? [2] (b) Give reason : Interhalogen compounds are more reactive than halogens (except fluorine). [1] 23. Write the balanced equations in the manufacture of K2Cr2O7 from chromite ore. 24. Explain the hybridization, geometry and magnetic property of [Co(NH3)6]3+ on the basis of valence bond theory [Atomic number Co = 27]. 25. With reference to the first transition series: (a) Name the metal which possesses maximum number of oxidation states. [1] (b) Among Zn2+ and Cu2+, which is colourless? [1] (c) Calculate the spin only magnetic moment of Fe2+. [1] 26. (a) Draw structures of geometrical isomers of [Fe (NH3)2 (CN)4] . [2] (b) Calculate the overall complex dissociation equilibrium constant for the [Cu(NH3)4]2+ ion, given 4 for this complex is 2.1 1013. [1] PART - D IV. Answer any THREE of the following questions (five marks each) [3 5 = 15] 27. (a) Calculate the packing efficiency in a face centred cubic (FCC) lattice. [3] (b) An element has body centred cubic (bcc) structure with cell edge of 288 pm and density of the element is 7.2 g cm 3. How many atoms are present in 208 g of the element? [2] 28. (a) 5.8 g of a non-volatile solute was dissolved in 100 g of carbon disulphide (CS2). The vapour pressure of the solution was found to be 190 mm of Hg. Calculate the molar mass of the solute. [Given: the vapour pressure of pure CS2 is 195 mm of Hg; [molar mass of CS2 = 76 g mol 1] (b) What are non-ideal solutions? Mention the reason for negative deviation from Raoult s law. 2P1617CPP1 2 [3] [2] 29. (a) Explain why 0m of a weak electrolyte cannot be determined graphically. How 0m and dissociation constant of the weak electrolyte are determined? [3] (b) Calculate the current strength in amperes required to liberate 10 g of chlorine by the electrolysis of NaCl solution in one hour. (Atomic mass of Cl = 35.5). [2] 30. (a) Derive the integrated rate equation for the rate constant of a first order reaction. [3] (b) Define (i) energy of activation (ii) temperature coefficient of a reaction [1+1] 31. (a) Mention two differences between physisorption and chemisorption. [2] (b) Explain the modern adsorption theory of heterogeneous catalysis. [2] (c) What is zeta potential? [1] V. Answer any FOUR of the following questions (five marks each) [4 5 = 20] 32. (a) Write the product formed in the following reactions: (i) + CH3 CH2 Cl anhydrous AlCl3 acetone (ii) CH 3CH 2 CH 2 Cl NaI heat light (iii) 2CHCl3 O2 [1 + 1 + 1] 2 (b) Explain SN mechanism with a suitable example. [2] 33. (a) Write the equation for (i) acetylation of salicylic acid (ii) tertiary butyl alcohol with copper catalyst at 573 K (iii) tertiary butyl methyl ether with HI (b) How is phenol manufactured by cumene process? [1 + 1 + 1] [2] 34. (a) What happens when carbonyl compounds are treated with 2, 4-dinitrophenylhydrazine? Write the equation. [2] (b) Explain HVZ (Hell-Volhard-Zelinsky) reaction with equation. [2] (c) Name the product formed when benzene is made to react with acetyl chloride in presence of anhydrous AlCl3. [1] 35. (a) How are primary, secondary and tertiary amines distinguished using Hinsberg reagent? Write the equations. [3] (b) Explain Hoffmann s bromamide degradation reaction for the preparation of methanamine. [2] 36. (a) How is the presence of five OH groups and the nature of the carbon chain in glucose determined? Write one limitation of open chain structure of glucose. [3] (b) What is denaturation of proteins? Which level of structure remains intact during denaturation of globular protein? [2] 37. (a) What are biodegradable polymers? Write the partial structure of PHBV. (b) What is copolymerisation? Give an example. [2] *** 2P1617CPP1 [3] 3

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