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#### Most expected three mark questions in Basic Concepts of Chemistry and Chemical Calculations - III

11th Standard

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Chemistry

Answer any fifty of the following questions
Time : 02:00:00 Hrs
Total Marks : 150

Part - A

54 x 3 = 162
1. Calculate the number of atoms/molecules present in the following 1Kg of acetic acid

2. The approximate production of Na2C03 per month is 424 x 106gwhile that of methyl alcohol is 320 x 106g. Which is produced more in terms of moles?

3. Calculate number of moles of carbon atoms in three .moles of ethane.

4. Find the molecular mass of FeSO47H2O.

5. Calculate the number of moles present in the following 50g of calcium chloride

6. Calculate the number of moles present in the following 120g of sodium hydroxide

7. Calculate the number of moles present in the following 46g of ethanol

8. Calculate the number of moles present in the following 90 g of magnesium oxide

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

10. The density of CO2 =1.977kgm-3 at STP. Calculate I the molecular mass of CO2

11. How many moles of glucose are present in 720g of glucose

12. Calculate the weight of 0.2 mole of sodium carbonate.

13. Calculate the equivalent mass of bicarbonate ion.

14. Calculate the molar volume of the following 88 g of CO2

15. Calculate the molar volume of the following 5 moles of methane

16. Calculate the molar volume of the following 460g of formic acid

17. Calculate the molar volume of the following 3.0115 $\times$1023 molecules of SO2 gas

18. Calculate the equivalent mass of the following: Zn

19. Calculate the equivalent mass of the following: nitrate ion (NO3-)

20. Calculate the equivalent mass of the following: Sodium

21. 0.456 g of a metal gives 0.606g of its chloride Calculate its equivalent mass

22. Decide whether each of the following reaction involves oxidation reduction reaction or not. If it does,identify which species is oxidised and which gets oxidised?
${ 4CH }_{ 3 }-\overset { \overset { O }{ || } }{ C } -{ CH }_{ 3 }+LiAl{ H }_{ 4 }={ 4H }_{ 2 }O\rightleftharpoons { 4CH }_{ 3 }-\overset { \overset { OH }{ || } }{ CH } -{ CH }_{ 3 }+LiOH+Al({ OH })_{ 3 }$

23. Decide whether each of the following reaction involves oxidation reduction reaction or not. If it does ,identify which species is oxidised and which gets oxidised?
${ CH }_{ 3 }{ CH }_{ 2 }OH\overset { { H }_{ 2 }{ SO }_{ 4 } }{ \longrightarrow } { CH }_{ 2 }={ CH }_{ 2 }+{ H }_{ 2 }O$

24. Decide whether each of the following reaction involves oxidation reduction reaction or not. If it does , identify which species is oxidised and which gets oxidised ?
${ CH }_{ 3 }-\overset { \underset { || }{ O } }{ C } -OH+{ CH }_{ 3 }{ NH }_{ 2 }\rightleftharpoons { CH }_{ 3 }-\overset { \underset { || }{ O } }{ C } -O^{ - }+{ CH }_{ 3 }{ NH }_{ 3 }^{ + }$

25. Calculate the equivalent mass of barium hydroxide

26. Boric acid, H3BO3 is a mild antiseptic and is often used as an eyewash. A sample contains 0.543 mol H3BO3. What is the mass of boric acid in the sample?

27. A compound contains 50% of X (atomic mass 10) and 50% Y (atomic mass 20). Give its molecular formula.

28. Determine the empirical formula of a compound containing K = 24.75%, Mn = 34.77% and rest is oxygen

29. Identify the type of redox reaction taking place in the following
$3{ M }^{ 0 }g_{ (s) }+{ N }_{ 2(g) }^{ 0 }\longrightarrow \overset { +2 }{ { Mg }_{ 3 } } \overset { -3 }{ N_{ 2(s) } }$

30. Identify the type of redox reaction taking place in the following
$\overset { +5 }{ { Y }_{ 2 } } \overset { -2 }{ { O }_{ 5(s) } } +5\overset { 0 }{ { Ca }_{ (s) } } \longrightarrow \overset { 0 }{ 2 } { V }_{ (s) }+\overset { +2 }{ 5 } \overset { -2 }{ { CaO }_{ (s) } }$

31. Identify the type of redox reaction taking place in the following
$\overset { +1 }{ 2K } \overset { +5 }{ Cl } \overset { -2 }{ O_{ 3(s) } } \longrightarrow 2\overset { +1 }{ K } \overset { -1 }{ { Cl }_{ (s) } } +3\overset { 0 }{ { O }_{ 2 }(g) }$

32. Identify the type of redox reaction taking place in the following
$\overset { 0 }{ { Ca }_{ (s) } } +\overset { +1 }{ 2 } \overset { -2 }{ { H }_{ 2 }O_{ (l) } } \longrightarrow \overset { +2 }{ Ca } \overset { -2+1 }{ { (0H) }_{ 2(aq) } } +\overset { 0 }{ H } _{ 2(g) }$

33. Identify the type of redox reaction taking place in the following
${ Br }_{ 2(1) }+2I_{ (aq) }\longrightarrow 2{ Br }_{ (aq) }^{ - }+{ I }_{ 2(s) }$

34. Identify the type of redox reaction taking place in the following
$\overset { 0 }{ { Cl }_{ 2(g) } } +{ 2OH^{ - }_{ (aq) } }\longrightarrow \overset { -1 }{ Cl } { O }_{ (aq) }^{ - }+\overset { -1 }{ { Cl }^{ - } } _{ (aq) }+{ H }_{ 2 }{ O }_{ (l) }$

35. Balance the following reaction:
K2Cr2O7 + KI + H2SO4 $\rightarrow$ K2SO4 + Cr2(SO4)3 + I2 + H2O

36. Balance the following reaction:
KMnO4 + Na2SO3$\rightarrow$MnO2 + Na2SO4 + KOH (Alkaline medium)

37. Balance the following redox reaction:
K2Cr2O7 + KCI + H2SO4 $\rightarrow$ KHSO4 + CrO2CI2 + H2O

38. Balance the following reaction:
Cu + HNO3$\rightarrow$Cu(NO3)2 + NO2 + H2O

39. What will be oxidation number of sulphur in${ S }_{ 2 }{ O }_{ 8 }^{ 2- }$ ions and ${ S }_{ 2 }{ O }_{ 6 }^{ 2- }$ ion?

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

41. Balance the following reaction:
P+5HNO3 $\rightarrow$ H3PO4 + 5NO2 + H2O

42. Balance the following reaction:
H2C2O4+KMnO4 + H2SO4 $\rightarrow$ H2SO4 + MnSO4 + CO2 + H2O

43. Balance the following reaction:
CuO+ NH3 $\rightarrow$Cu + N2+ H2O

44. Balance the following reaction:
Zn + HNO3 $\rightarrow$ Zn (NO3)2 + NH4NO3 +H2O

45. Balance the following reaction:
MnO-4 + Sn2+$\rightarrow$ Mn2+ + Sn4+

46. Balance the following reaction:
MnO42-$\rightarrow$ MnO42- + MnO2

47. Balance the following reaction:
MnO4- + Fe2+ $\rightarrow$ Mn2+ + Fe3+

48. Balance the following reaction:
S2O32- + I2$\rightarrow$S2O62- + I-

49. a) 0.456 g of a metal gives 0.606 g of its chloride. Calculate the equivalent mass of the metal.
b) Calculate the equivalent mass of potassium dichromate. The reduction half-reaction in acid medium is Cr2072- + 14H+ 6e- $\rightarrow$ 2Cr3++7H20

50. Experimental analysis of a compound containing the elements x,y,z on analysis gave the following data.
x = 32 %, y = 24 %, z = 44 %. The relative number of atoms of x, y and z are 2, 1 and 0.5, respectively. (Molecular mass of the compound is 400 g) Find out.
i) The atomic masses of the element x,y,z.
ii) Empirical formula of the compound and
iii) Molecular formula of the compound

51. The balanced equation for a reaction is given below 2x+3y $\rightarrow$ 41+ m
When 8 moles of x react with 15 moles of y, then
i) Which is the limiting reagent?
ii) Calculate the amount of products formed.
ill) Calculate the amount of excess reactant left at the end of the reaction

52. Balance the following reaction:
C2O42-+Cr2O72-$\rightarrow$Cr3++CO2

53. Balance the following reaction
S2O32- +I$\rightarrow$ SO42- + I-

54. Balance the following reaction:
Sb3++ Mn${ O }_{ 4 }^{ - }$$\rightarrow$ Sb5++ Mn2+