#### 11th Public Exam March 2019 Important 5 Marks Questions

11th Standard

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Chemistry

Time : 02:30:00 Hrs
Total Marks : 300
60 x 5 = 300
1. Calculate the molar mass of the following compounds. -
i) urea [CO(NH2)2]
ii) acetone [CH3 COCH3]
iii) boric Acid [H3BO3]
iv) Sulphurci  Acid [H2SO4]

2. The reaction between aluminum and ferric oxide can generate temperatures up to 3273 K and is used in welding metals. (Atomic mass of AC = 27 u atomic mass of O = 16 u )
2Al + Fe2O3 $\longrightarrow$ Al2O3 + 2Fe;  If in this process, 324 g of aluminum is allowed to react with 1.12 kg of ferric oxide
i) Calculate the mass of Al2O3 formed
ii) How much of the excess reagent is left at the end of the reaction?

3. Write note on decomposition reaction

4. Balance the following equations by oxidation number method
i) ${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }+KI+{ H }_{ 2 }SO_{ 4 }\longrightarrow { K }_{ 2 }{ SO }_{ 4 }+{ Cr }_{ 2 }({ SO }_{ 4 })+{ I }_{ 2 }+{ H }_{ 2 }O$
ii) ${ K }Mno_{ 4 }+{ Na }_{ 2 }{ So }_{ 3 }\longrightarrow { MnO }_{ 2 }+{ Na }_{ 2 }{ So }_{ 4 }+KOH$
iii) $Cu+{ HNO }_{ 3 }\longrightarrow Cu\left( { No }_{ 3 } \right) _{ 2 }+{ No }_{ 2 }+{ H }_{ 2 }O$
iv) ${ KMn }O_{ 4 }+{ H }_{ 2 }{ C }_{ 2 }{ O }_{ 4 }+{ H }_{ 2 }{ SO }_{ 4 }\longrightarrow { K }_{ 2 }{ SO }_{ 4 }+{ MnSO }_{ 4 }+{ CO }_{ 2 }+{ H }_{ 2 }O$

5. Explain the term competitive electron transfer reaction with an example.

6. Balance the following equations by oxidation number method.
NH3 + F2 ⟶ HF + N2

7. Balance the following equation by ion-electron method In acidic medium.
$Sb^{3+}{MnO}_4^{-} \rightarrow Sb^{5+}+Mn^{2+}$

8. A laboratory analysis of an organic compound gives the following mass percentage composition: C = 60%, H = 4.48% and remaining oxygen.

9. Enlist the postulates of Bohr's atom model.

10. Derive an equation for the wavelength of a matter wave.

11. The Li2+ ion is a hydrogen like. ion that can be described by the Bohr model. Calculate the Bohr radius of the third orbit and calculate the energy of an electron in 4th orbit.

12. Suppose that the uncertainty in determining the position of an electron in an orbit is 0.6 $\mathring{A}$ . What is the uncertainty in its momentum

13. The uncertainty in the position and velocity of a particle are 10-2 m and $5.27\times { 10 }^{ -24 }{ ms }^{ -1 }$ respectively. Calculate the mass of the particle

14. Calculate the de Broglie wavelength of an electron that has been accelerated from rest through 1potential differences of 1 KV.

15. Calculate the uncertainty in the position of an electron, if the uncertainty in its velocity is 5.7 x 105 ms-1.

16. Derive de Broglie equation and give its significance.

17. Explain the periodic trend of ionisation potential.

18. By using paulings method calculate the ionic radii of K+ and CI- ions in the potassium chloride crystal. Given that dk+-cl-=3.14 Å.

19. How do you classify of elements into blocks? Give their electronic configuration.

20. What are the factors which influence the electron gain enthalpy?

21. What are the factors influencing ionization enthalpy.

22. Explain about the anomalies of Mendeleev's periodic table.

23. A group metal (A) which is present in common salt reacts with (B) to give compound (C) in which hydrogen is present in -1 oxidation state. (B) on reaction with a gas -gives universal solvent (D). The compound (D) reacts with (A) to give (E), a strong base. Identify A, B, C, D and E. Explain the reactions.

24. Conc. H2SO4 cannot be used for drying hydrogen gas. Why?

25. Explain the exchange reactions of heavy water

26. Define hydrogen bond and its types.

27. Give a brief account of the action of water on metals.

28. Explain the important common features of Group 2 elements.

29. How are peroxides and superoxides formed by alkali metals?

30. Explain the preparation and uses of the following compounds of calcium.

31. Describe the method of electrolysis of brine solution?

32. Explain whether a gas approaches on ideal behavior or deviates from ideal behaviour if
(a) it is compressed to a smaller volume at constant temperature.
(b) the temperature is raised at while keeping the volume constant
(c) more gas is introduced into the same volume and at the same temperature

33. Derive the ideal gas equation by combining the empirical gas laws.

34. Using Dalton's law how will you determine the pressure of a dry gas.

35. The vanderwaal's constants a = 2.095 lit2 atm mol-1 and b = 0.0189 lit mol-1 respectively. Calculate the inversion temperature.

36. Find the ratio of effusion rates of hydrogen and krypton gas.

37. At sea level a balloon has volume of 785 x10-3dm3 What will be its volume, if it taken to a place where the pressure is 0052 atm. Less than the atmospheric pressure of 1 atm.

38. A tank contains a mixture of 52.5g of Oxygen and 65.1g of CO2 at 300 K the total pressure in the tanks is 9.21 atm. calculate the partial pressure (in atm.) of each gas in the mixture.

39. Calculate the total pressure in a mixture of 8 g of oxygen and 4 g of hydrogen confined in a vessel of 1 dm3 at 27° C. [R = 0.083 bar dm3 K-1 mol-1.]

40. Define the following terms
(a) isothermal process (b) adiabatic process
(c) isobaric process (d) isochoric process

41. Calculate the entropy change in the system, and surroundings, and the total entropy change in the universe during a process in which 245 J of heat flow out of the system at 77°C to the surrounding at 33°C.

42. For the reaction Ag2O(s) ⟶2Ag(s) + $\frac{1}{2}$O2(g) : ΔH =30.56 kJ mol-1 and AS = 6.66JK-1 mol-1 (at 1 atm). Calculate the temperature at which ΔG is equal to zero. Also predict the direction of the reaction (i) at this temperature and (ii) below this temperature.

43. A gas mixture of 3.67 lit of ethylene and methane on complete combustion at 25°C and at 1 atm pressure produce 6.11 lit of carbondioxide. Find out the amount of heat evolved in kJ, during this combustion. (ΔHc(CH4)= - 890 kJ mol-1 and (ΔHc(C2H4) = -1423 kJ mol-1

44. Calculate the standard entropy change for the following reaction (Δsf0), given the standard entropies of CO2(g) ,  C(s) 'O2(g) as 213.6, 5.740, and 205 JK-1 respectively.

45. In the reaction N2(g) + O2(g) ⟶ 2NO(g), ΔH0 reaction is 179.9 KJ mol-1 and  ΔS0reaction=78.09 JK-1mol-1. Calculate ΔG0reaction at 300 K.

46. From the following data,
CH4+2O➝ CO2+2H2O    ΔHo= -890 KJ mol-1
H2O(l) ➝ H2O(g)     ΔHo= 44 KJ mol-1 at 298 K
Calculate the enthalpy of the reaction
CH4+2O2 ➝ CO2+2H2O     ΔHo=?

47. Derive the various mathematical statements of the first law.

48. The atmospheric oxidation of NO
2NO(g) + O2(g) ⇌ 2NO2(g)
was studied with initial pressure of 1 atm of NO and 1 atm of O2. At equilibrium, partial pressure of oxygen is 0.52 atm calculate Kp of the reaction.

49. The partial pressure of carbon dioxide in the reaction
CaCO3 (s) ⇌ CaO (s) + CO2(g) is 1.017 × 10–3 atm at 5000 C. Calculate KP at 6000c C for the reaction. ΔH for the reaction is 181 KJ mol–1 and does not change in the given range of temperature.

50. 2.56 g of Sulphur is dissolved in 100g of carbon disulphide. The solution boils at 319. 692 K. What is the molecular formula of Sulphur in solution The boiling point of CS2 is 319. 450K. Given that Kb for CS2 = 2.42 K Kg mol-1.

51. Explain the positive deviation exhibited by nonideal solutions with preference to a solution of ethyl alcohol and water

52. Discuss the stepwise determination of the (Lewis)  structure of nitric acid.

53. How are bonding and anti-bonding molecular orbitals formed? Represent the constructive and destructive interaction in the 1s orbitals.

54. 0.26g of an organic compound gave 0.039 g of water and 0.245 g of carbon dioxide on combustion. Calculate the percentage of C & H.

55. List down the characteristics possessed by the organic compounds.

56. Discuss the principle and procedure involved in estimating the amount of sulphur present in an organic compound.

57. Give a detailed account on homolytic and heterolytic cleavage.

58. Identify the compound A, B, C and D in the following series of reactions

Write short notes on ortho, para directors in aromatic electrophilic substitution reactions.

59. Ethane burns completely in air to give CO2, while in a limited supply of air gives CO. The same gases are found in automobile exhaust. Both CO and CO2 are atmospheric pollutants
i) What is the danger associated with these gases
ii) How do the pollutants affect the human body?

60. What are non-viable particulates? How are they classified? Explain.