#### +1 Public Exam March 2019 Important Creative 3 Mark Questions and Answers

11th Standard

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Chemistry

Time : 02:30:00 Hrs
Total Marks : 210
70 x 3 = 210
1. Calculate the oxidation number of underlined atoms of the following:
K2CrO4

2. Calculate the equivalent mass of potassium dichromate in acid medium
[K2Cr2O7 + 4H2SO4 )$\rightarrow$K2SO4 + Cr2(SO4)3 +4H2O + 3(O) 3 x 16 = 48 294 g]

3. Calculate the oxidation number of underlined atoms${ C }_{ \underline { 6 } }{ H }_{ 12 }{ O }_{ 6 }$

4. Calculate the number of moles present in the following 19.5g of potassium

5. Calculate the equivalent mass of barium hydroxide

6. Balance the following reaction:
P+ HNO3$\rightarrow$ H3PO4 + NO2 + H2O

7. The relative abundance of 6C12,6C13and 6C14are 98.892%, 1.108% and 2 x 10-10respectively. Calculate the average atomic mass of carbon.

8. What is the amount of silver oxide formed when 11.04g of silver carbonate is strongly heated? Write the balanced chemical equation for the .reaction. Ag2C03 $\rightarrow$2AgO + CO2.

9. Define equivalent mass of a salt.

10. Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% oxygen by mass

11. How much volume of chlorine is required to form 11.2 L of HCI at 273 K and 1 atm pressure?

12. Using s, p, d notations, describe the orbital with the following quantum numbers.
(i) n =1 ,l = 0 ,(ii) n = 3, l= 1 (iii)n = 4, l= 2 (iv) n =4 , l = 3

13. Describe the Autbau principle

14. Explain the shapes of p orbitals

15. What is Stark effect?

16. Calculate the kinetic energy of a moving electron which has a wavelength 4.8 pm. (mass of electron = 9.11 x 10-31 kg, h = 6.63 x 10-34 JS)

17. Explain the meaning of the symbol 4f2. Write all the four quantum numbers for these electrons.

18. Justify that the fifth period of the periodic table should have 18 elements on the basis of quantum numbers.

19. Describe in brief Lothar Meyer's classification of elements.

20. Predict the position of the element having an electron configuration(n -1) d1 ns2 for n = 4.

21. Draw a simplified form of periods and elements present in modern period table.

22. Explain about the classification of elements based on electronic configuration.

23. Explain about the salient features of metals.

24. How do you expect the metallic hydrides to be useful for hydrogen storage?

25. What kind of compounds can be dissolved and hydrolysed in water?

26. Give a brief account of the action of water on non metals

27. Explain the different methods of preparation of Tritium with equation.

28. What are metallic hydrides? Explain about it.

29. Write the chemical equations for the reactions involved in solvay process of preparation of sodium carbonate.

30. Why is the density of potassium less than that of sodium?

31. IE2 values of alkaline earth metals are much smaller than those of alkali metals. Explain

32. How would you explain the following observation? BeO is almost insoluble but BeSO4 is soluble in water.

33. Explain how alkali metal oxide reacts with water?

34. Copper and chlorine compounds makes blue fire work. Why?

35. State Boyle's law.

36. One mol of SO2 gas occupies a volume of 500 ml at 27°C and 50 atm pressure. Calculate the compressibility factor of the gas. Comment on the type of deviation shown by the gas from the ideal behaviour.

37. Explain Charles' law with an experimental illustration.

38. Explain the graphical representation of Charles' law.

39. 30.4 kJ is required to melt one mole of sodium chloride. The entropy change during melting is 28.4 JK-1 mol-1. Calculate the melting point of sodium chloride.

40. Define work.

41. What is the need for second Law of thermodynamics.

42. Define entropy of fusion.

43. What are informations do you get from the thermo chemical equations?

44. Given N2(g) + 3H2(g) $\rightarrow$ 2NH3(g); $\Delta$H°=-92.4 kJ mol-1. What is the standard enthalpy of formation of NH3(g)?

45. Calculate ΔHr0 for the reaction CO2(g) + H2(g) ⟶ CO(g) + H2O (g) given that ΔHf0 for CO2 (g), CO (g) and H2O (g) are - 393.5, - 111.31 and - 242 kJ mol-1 respectively.

46. The value of Kc for the following reaction at 717 K is 48.

47. List out few examples of irreversible reactions (changes) taking place in our daily life activity.

48. Discuss the equilibrium involving dissolution of solids or gases in liquids.

49. What happens when the' concentration of H2 and I2 are increased in the reaction ${ H }_{ 2 }+{ I }_{ 2 }\rightleftharpoons 2HI?$

50. Ethylene glycol (C2H6O2) can be at used as an antifreeze in the radiator of a car. Calculate the temperature when ice will begin to separate from a mixture with 20 mass percent of glycol in water used in the car radiator. Kf for water = 1.86 K Kg mol-1 and molar mass of ethylene glycol is 62 g mol-1.

51. A sample of 56g of ethanol is dissolved in 36g of. water. Calculate the mole fraction of ethyl alcohol

52. How much volume of 6 M solution of NaOH is required to prepare 500 mL of 0.250 M NaOH solution?

53. NaOH and HCI react to form NaCI and H20 (a) What volume of 0.250 M NaOH solution contains 0.110 mol of NaOH (b) What of volume of 0.20 M NaOH is required to exactly react with 0.150mol HCI?

54. Calculate the boiling point of a solution which is prepared by dissolving 68.4g of solute 8 in one kilogram of water. (Molar mass of solute 8 is 342 g mol1, Tb= 373.1K and Kb( water) = 0.52 K kg mol1.

55. What is covalent bond? Give suitable examples to represent single, double and triple covalent bonds.

56. Comment on the following statements. .
(i) BF3 is planar but NH3 is not.
(ii) SiF4 and C/O-4 are tetrahedral
(iii) HSH bond angle in H2S is 92° and HOH bond angle in H20 is 104.5.

57. (i) Calculate the bond order of H2 and B2
(ii) Show how the bond order is related to stability and bond length of the molecule.

58. 0.16 g of an organic compound was heated in a carius tube and H2SO4 acid formed was precipitated with BaCl2. The mass of BaSO4 was 0.35g. Find the percentage of sulphur [30.04]

59. Write a short note on homologous series.

60. Represent and explain the structures of acetaldoxime.

61. Suggest and explain the method suitable to purify the organic compounds depending on their boiling points.

62. While writing the resonance structures, what are the rules to be followed?

63. Which of the following compounds will not exist as resonance hybrid? Give reason for your answer.
(i) CH3 - OH
(ii) R-CONH2
(iii) CH3-CH = CH-CH2NH2

64. Explain the isomerism exhibited by alkenes.

66. Two isomers (A) and (B) have the same molecular formula C2H4Cl2. Compound (A) reacts with aqueous KOH gives compound (C) of molecular formula C2H4O. Compound (B) reacts with aqueous KOH gives compound(D) of molecular formula C2H6O2. Identify (A), (B), (C) and (D).

67. How does bromo ethane react with the following?
(i) Silver Oxide(moist)
(ii) Sodium hydrogen sulphide
(iii) Potassium cyanide

68. Haloalkanes produce mixture of olefins- say true or false and justify yoyr answer,

69. From where does ozone come in the photo chemical smog?

70. Bring out the differences between classical and photochemical smog