\section{TOPIC 1: Measurement, Significant Figures and Laws of Chemical Combination}

1. Which has highest weight?

1) \(1 \mathrm{~m}^{3}\) of water

2) A normal adult man

3) 10 litre of \(\mathrm{Hg}\)

4) All have same weight

2. Arrange the numbers in increasing no. of significant figures. \(0.002600,2.6000,2.6,0.260\)

1) \(2.6<0.260<0.002600<2.6000\)

2) \(2.6000<2.6<0.002600<0.260\)

3) \(0.260<2.6<0.002600<2.6000\)

4) \(0.002600<0.260<2.6<2.6000\)

3. In which of the following number all zeros are significant?

1) 0.0005

2) 0.0500

3) 50.000

4) 0.0050

4. Which of the following is the best example of law of conservation of mass?

1) \(12 \mathrm{~g}\) of carbon combines with \(32 \mathrm{~g}\) of oxygen to form \(44 \mathrm{~g}\) of \(\mathrm{CO}_{2}\).

2) When \(12 \mathrm{~g}\) of carbon is heated in a vacuum there is no change in mass.

3) A sample of air increases in volume when heated at constant pressure but its mass remains unaltered.

4) The weight of a piece of platinum is the same before and after heating in air.

5. The percentage of copper and oxygen in samples of \(\mathrm{CuO}\) obtained by different methods were found to be the same. This illustrates the law of

1) constant proportions 2 ) conservation of mass

3) multiple proportions

4) reciprocal proportions

6. One of the following combination which illustrates the law of reciprocal proportions?

1) \(\mathrm{N}_{2} \mathrm{O}_{3}, \mathrm{~N}_{2} \mathrm{O}_{4}, \mathrm{~N}_{2} \mathrm{O}_{5}\) 2) \(\mathrm{NaCl}, \mathrm{NaBr}, \mathrm{NaI}\)

3) \(\mathrm{CS}_{2}, \mathrm{CO}_{2}, \mathrm{SO}_{2}\)

4) \(\mathrm{PH}_{3}, \mathrm{P}_{2} \mathrm{O}_{3}, \mathrm{P}_{2} \mathrm{O}_{5}\)

7. The molecular weight of \(\mathrm{O}_{2}\) and \(\mathrm{SO}_{2}\) are 32 and 64 respectively. At \(15^{\circ} \mathrm{C}\) and \(150 \mathrm{~mm} \mathrm{Hg}\) pressure, one litre of \(\mathrm{O}_{2}\) contains ' \(\mathrm{N}\) ' molecules. The number of molecules in two litres of \(\mathrm{SO}_{2}\) under the same conditions of temperature and pressure will be :

1) \(N / 2\)

2) \(1 \mathrm{~N}\)

3) \(2 \mathrm{~N}\)

4) \(4 \mathrm{~N}\)

8. \(10 \mathrm{dm}^{3}\) of \(\mathrm{N}_{2}\) gas and \(10 \mathrm{dm}^{3}\) of gas \(\mathrm{X}\) at the same temperature contain the same number of molecules, the gas \(\mathrm{X}\) is

1) \(\mathrm{CO}_{2}\)

2) \(\mathrm{CO}\)

3) \(\mathrm{H}_{2}\)

4) \(\mathrm{NO}\)

9. What is the mass of 1 molecule of \(\mathrm{CO}\) ?

\section{TOPIC 2: Mole Concept}

1) \(2.325 \times 10^{-23}\)

2) \(4.65 \times 10^{-23}\)

3) \(3.732 \times 10^{-23}\)

4) \(2.895 \times 10^{-23}\)

10. How many atoms are contained in one mole of sucrose \(\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)\) ?

1) \(20 \times 6.02 \times 10^{23}\) atoms \(/ \mathrm{mol}\)

2) \(45 \times 6.02 \times 10^{23}\) atoms \(/ \mathrm{mol}\)

3) \(5 \times 6.02 \times 10^{23}\) atoms \(/ \mathrm{mol} \mathrm{4)} \mathrm{None} \mathrm{of} \mathrm{these}\)

11. Molecular mass is defined as the

1) mass of one atom compared with the mass of one molecule

2) mass of one atom compared with the mass of one atom of hydrogen 

3) mass of one molecule of any substance compared with the mass of one atom of C-12

4) None of the above

12. Two containers \(\mathrm{P}\) and \(\mathrm{Q}\) of equal volume (1 litre each) contain \(6 \mathrm{~g}\) of \(\mathrm{O}_{2}\) and \(\mathrm{SO}_{2}\) respectively at \(300 \mathrm{~K}\) and 1 atmosphere, then

1) number of molecules in \(P\) is less than that in \(Q\).

2) number of molecules in \(P\) and \(Q\) is same.

3) number of molecules in \(Q\) is less than that in \(P\).

4) either 1) or 2 ).

13. A sample of \(\mathrm{AlF}_{3}\) contains \(3.0 \times 10^{24} \mathrm{~F}^{-}\)ions. The number of formula unit of this sample are

1) \(9 \times 10^{24}\)

2) \(3 \times 10^{24}\)

3) \(0.75 \times 10^{24}\)

4) \(1.0 \times 10^{24}\)

14. Which one of the following is the lightest?

1) 0.2 mole of hydrogen gas

2) \(6.023 \times 10^{22}\) molecules of nitrogen

3) \(0.1 \mathrm{~g}\) of silver

4) 0.1 mole of oxygen gas

15. The average atomic mass of neon based on following data is:

\(\begin{array}{ll}\text { Isotope } & \text { Relative abundance } \\ { }^{20} \mathrm{Ne} & 0.9051 \\ { }^{21} \mathrm{Ne} & 0.0027 \\ { }^{22} \mathrm{Ne} & 0.0922\end{array}\)

1) \(0.33 \mathrm{u}\)

2) \(20.187 \mathrm{u}\)

3) \(6.729 \mathrm{u}\)

4) \(18.058 \mathrm{u}\)

16. The ratio of number of oxygen atoms \((\mathrm{O})\) in \(16.0 \mathrm{~g}\) ozone \(\left(\mathrm{O}_{3}\right), 28.0\) g carbon monoxide (CO) and 16.0 oxygen \(\left(\mathrm{O}_{2}\right)\) is (Atomic mass : \(\mathrm{C}=12, \mathrm{O}=16\) and Avogadro's constant \(\mathrm{NA}=6.023 \times 10^{23} \mathrm{~mol}^{-1}\) )

1) \(3: 1: 2\)

2) \(1: 1: 2\)

3) \(3: 1: 1\)

4) \(1: 1: 1\)

17. A mixture of \(\mathrm{CH}_{4}, \mathrm{~N}_{2}\) and \(\mathrm{O}_{2}\) is enclosed in a container of 1 litre capacity at \(0^{\circ} \mathrm{C}\). Total pressure of gaseous mixture is \(2660 \mathrm{~mm} \mathrm{Hg}\). If the ratio of partial pressures of the gases is \(1: 4: 2\) respectively, the number of moles of oxygen present in the vessel is:

1)1/ 22.4

2) 1.0

3) 0.1

4) none of these

18. The number of gram molecules of oxygen in \(6.02 \times 10^{24} \mathrm{CO}\) molecules is

1) 10 g molecules 2) 5 g molecules

3) \(1 \mathrm{~g}\) molecules

4) 0.5 g molelcules

19. The number of molecules in \(16 \mathrm{~g}\) of methane is

1) \(3.0 \times 10^{23}\)

2) \(\frac{16}{6.02} \times 10^{23}\)

3) \(6.023 \times 10^{23}\)

4) \(\frac{16}{3.0} \times 10^{23}\)

20. \(25.4 \mathrm{~g}\) of \(\mathrm{I}_{2}\) and \(14.2 \mathrm{~g}\) of \(\mathrm{Cl}_{2}\) are made to react completely to yield a mixture of ICl and \(\mathrm{ICl}_{3} . \mathrm{Calculate}^{2}\) moles of \(\mathrm{ICl}\) and \(\mathrm{ICl}_{3}\) formed

1) \(0.1,0.1\)

2) \(0.2,0.2\)

3) \(0.1,0.2\)

4) \(0.2,0.1\)

21. If we consider that \(1 / 6\), in place of \(1 / 12\), mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

1) decrease twice

2) increase two fold

3) remain unchanged

4) be a function of the molecular mass of the substance

22. Number of moles of \(\mathrm{MnO}^{4-}\) required to oxidize one mole of ferrous oxalate completely in acidic medium will be

1) 0.6 moles

2) 0.4 moles

3) 7.5 moles

4) 0.2 moles

23. The number of moles of oxygen in one litre of air containing \(21 \%\) oxygen by volume, under standard conditions are

1) 0.0093 mole

2) 0.21 mole

3) 2.10 mole

4) 0.186 mole

24. Haemoglobin contains \(0.334 \%\) of iron by weight. The molecular weight of haemoglobin is approximately 67200. The number of iron atoms (at. wt. of Fe is 56) present in one molecule of haemoglobin are

1) 1

2) 6

3) 4

4) 2

25. How many moles of \(\mathrm{P}_{4} \mathrm{O}_{6}\) and \(\mathrm{P}_{4} \mathrm{O}_{10}\) will be produced by the combustion of \(12.4 \mathrm{~g}\) of phosphorous (atomic mass 31) in \(12.8 \mathrm{~g}\) of oxygen, leaving no \(\mathrm{P}_{4}\) or \(\mathrm{O}_{2}\) ?

1) 0.1 and \(0.3 \mathrm{~mol}\)

2) \(0.15 \mathrm{~mol}\) and \(0.25 \mathrm{~mol}\)

3) \(0.05 \mathrm{~mol}\) each

4) \(0.1 \mathrm{~mol}\) each 

\section{TOPIC 3: Atomic, Molecular Masses, Equivalent Masses and Expression of Concentration}

26. Number of atoms in \(558.5 \mathrm{~g} \mathrm{Fe}\) (at. wt. of \(\mathrm{Fe}=55.85 \mathrm{~g} \mathrm{~mol}^{-1}\) ) is

1) twice that in 60 g carbon

2) \(6.023 \times 10^{22}\)

3) half that in \(8 \mathrm{~g} \mathrm{He}\)

4) \(558.5 \times 6.023 \times 10^{23}\)

27. The percentage weight of \(\mathrm{Zn}\) in white vitriol \(\left[\mathrm{ZnSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}\right]\) is approximately equal to \((\mathrm{Zn}=65, \mathrm{~S}=32\), \(\mathrm{O}=16\) and \(\mathrm{H}=1)\)

1) \(33.65 \%\)

2) \(32.56 \%\)

3) \(23.65 \%\)

4) \(22.65 \%\)

28. The vapour density of a mixture containing \(\mathrm{NO}_{2}\) and \(\mathrm{N}_{2} \mathrm{O}_{4}\) is 27.6 . Mole fraction of \(\mathrm{NO}_{2}\) in the mixture is

1) 0.2

2) 0.4

3) 0.6

4) 0.8

29. The number of molecules in 8.96 litre of a gas at \(0^{\circ} \mathrm{C}\) and 1 atm. pressure is approximately

1) \(6.023 \times 10^{23}\)

2) \(12.04 \times 10^{23}\)

3) \(18.06 \times 10^{23}\)

4) \(24.08 \times 10^{22}\)

30. Suppose two elements \(X\) and \(Y\) combine to form two compounds \(X Y_{2}\) and \(X_{3} Y_{2}\) when 0.1 mole of former weighs \(10 \mathrm{~g}\) while \(0.05 \mathrm{~mol}\) of the latter weights \(9 \mathrm{~g}\). The atomic masses of \(\mathrm{X}\) and \(\mathrm{Y}\) are respectively

1) \(60 \& 40\)

2) \(30 \& 40\)

3) \(40 \& 30\)

4) \(40 \& 60\)

31. \(4 \mathrm{~g}\) of a hydrated crystal of formula A. \(x \mathrm{H}_{2} \mathrm{O}\) has \(0.8 \mathrm{~g}\) of water. If the molar mass of the anhydrous crystal 1) is \(144 \mathrm{~g} \mathrm{~mol}^{-1}\), The value of \(\mathrm{x}\) is

1) 4

2) 1

3) 2

4) 3

32. \(6.02 \times 10^{20}\) molecules of urea are present in \(100 \mathrm{~mL}\) of its solution. The concentration of solution is

1) \(0.01 \mathrm{M}\)

2) \(0.001 \mathrm{M}\)

3) \(0.1 \mathrm{M}\)

4) \(0.02 \mathrm{M}\)

33. A metallic chloride contain \(47.22 \%\) metal. Calculate the equivalent weight of metal.

1) 39.68

2) 31.76

3) 36.35

4) 33.46

34. Sulphur forms the chlorides \(\mathrm{S}_{2} \mathrm{Cl}_{2}\) and \(\mathrm{SCl}_{2}\). The equivalent mass of sulphur in \(\mathrm{SCl}_{2}\) is

1) \(8 \mathrm{~g} / \mathrm{mol}\)

2) \(16 \mathrm{~g} / \mathrm{mol}\)

3) \(64.8 \mathrm{~g} / \mathrm{mol}\)

4) \(32 \mathrm{~g} / \mathrm{mol}\)

35. If \(0.20 \mathrm{~g}\) chloride of a certain metal, when dissolved in water and treated with excess of \(\mathrm{AgNO}_{3}\), yields \(0.50 \mathrm{~g}\) of \(\mathrm{AgCl}\), the equivalent mass of the metal is \((\mathrm{Ag}=108, \mathrm{Cl}=35.5)\)

1) 21.90

2) 20.04

3) 40.08

4) 43.80

36. Equivalent mass of a metal \(M\) is 2.5 times that of oxygen. The minimum molecular mass of its oxide is

1) 28

2) 42

3) 56

4) 112

37. The same amount of a metal combines with \(0.100 \mathrm{~g}\) of oxygen and with \(1.000 \mathrm{~g}\) of a halogen. Hence, the equivalent mass of halogen is

1) 9

2) 35.5

3) 80

4) 127

38. In the reaction \(\mathrm{NaOH}+\mathrm{Al}(\mathrm{OH})_{3} \rightarrow \mathrm{NaAlO}_{2}+\mathrm{H}_{2} \mathrm{O}\) The equivalent mass of \(\mathrm{Al}(\mathrm{OH})_{3}\) is

1) 78

2) 26

3) 52

4) unpredictable

39. On reduction \(1.644 \mathrm{~g}\) of hot iron oxide give \(1.15 \mathrm{~g}\) of iron. Evaluate the equivalent weight of iron.

1) 18.62

2) 19.13

3) 18.95

4) 12.95

40. If a pure compound is composed of \(X_{2} Y_{3}\) molecules and consists of \(60 \%\) of \(X\) by weight, the atomic weight of \(Y\) is

1) 2.25 times atomic weight of \(X\)

2) \(44 \%\) of atomic weight of \(X\)

3) 4.0 times the atomic weight of \(X\)

4) \(25 \%\) of the atomic weight of \(X\)

41. Oxalic acid \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\) reacts with permanganate ion according to the balanced equation below. How many mL of \(0.0154 \mathrm{KMnO}_{4}\) solution are required to react with \(25.0 \mathrm{~mL}\) of \(0.0208 \mathrm{M} \mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\) solution? \(5 \mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{MnO}_{4}^{-}(\mathrm{aq})+6 \mathrm{H}^{+}(\mathrm{aq}) \rightarrow 2 \mathrm{Mn}^{2+}(\mathrm{aq})+10 \mathrm{CO}_{2}(\mathrm{~g})+8 \mathrm{H}_{2} \mathrm{O}(1)\)

1) \(13.5 \mathrm{~mL}\)

(2) \(18.5 \mathrm{~mL}\)

(3) \(33.8 \mathrm{~mL}\)

(4) \(84.4 \mathrm{~mL}\)

42. Percentage of Se in peroxidase anhydrase enzyme is \(0.5 \%\) by weight (at. wt. of Se \(=78.4)\) then minimum molecular weight of peroxidase anhydrase enzyme is

1) \(1.568 \times 10^{3}\)

2) 15.68

3) \(2.136 \times 10^{4}\)

4) \(1.568 \times 10^{4}\)

43. Liquid benzene \(\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)\) burns in oxygen according to the equation

\[

2 \mathrm{C}_{6} \mathrm{H}_{6}(1)+15 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 12 \mathrm{CO}_{2}(\mathrm{~g})+6 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})

\]

How many litres of \(\mathrm{O}_{2}\) at STP are needed to complete the combustion of 39 g of liquid benzene?(Mol. wt. of \(\left.\mathrm{O}_{2}=\quad 32, \mathrm{C}_{6} \mathrm{H}_{6}=78\right)\)

1) \(74 \mathrm{~L}\)

2) \(11.2 \mathrm{~L}\)

3) \(22.4 \mathrm{~L}\)

4) \(84 \mathrm{~L}\)

44. The mass of \(\mathrm{BaCO}_{3}\) produced when excess \(\mathrm{CO} 2\) is bubbled through a solution of \(0.205 \mathrm{~mol} \mathrm{Ba}(\mathrm{OH})_{2}\) is

1) \(81 \mathrm{~g}\)

2) \(40.5 \mathrm{~g}\)

3) \(20.25 \mathrm{~g}\)

4) \(162 g\)

45. \(12 \mathrm{~L}\) of \(\mathrm{H}_{2}\) and \(11.2 \mathrm{~L}\) of \(\mathrm{Cl}_{2}\) are mixed and exploded. Find the composition by volume of mixture.

1) \(11.2,11.2,22.4\)

2) \(0.8,0,22.4\)

3) \(0.8,0.8,22.4\)

4) \(0.8,11.2,22.4\)

46. 10 moles \(\mathrm{SO}_{2}\) and 15 moles \(\mathrm{O}_{2}\) were allowed to react over a suitable catalyst. 8 moles of \(\mathrm{SO}_{3}\) were formed. The remaining moles of \(\mathrm{SO}_{2}\) and \(\mathrm{O}_{2}\) respectively are -

1) 2 moles, 11 moles

2) 2 moles, 8 moles

3) 4 moles, 5 moles

4) 8 moles, 2 moles

47. How many moles of \(\mathrm{KI}\) are required to produce 0.4 moles of \(\mathrm{K}_{2} \mathrm{HgI}_{4}\) ?

1) 0.4

2) 0.8

3) 3.2

4) 1.6

48. Under similar conditions of pressure and temperature, \(40 \mathrm{~mL}\) of slightly moist hydrogen chloride gas is mixed with \(20 \mathrm{~mL}\) of ammonia gas, the final volume of gas at the same temperature and pressure will be

1) \(100 \mathrm{~mL}\)

2) \(20 \mathrm{~mL}\)

3) \(40 \mathrm{~mL}\)

4) \(60 \mathrm{~mL}\)

49. What is the volume of \(\mathrm{CO}_{2}\) liberated (in litres) at 1 atmosphere and \(0^{\circ} \mathrm{C}\) when \(10 \mathrm{~g}\) of \(100 \%\) pure calcium carbonate is treated with excess dilute sulphuric acid?

(Atomic mass Ca : 40, C:12, O : 16)

1) 0.224

2) 2.24

3) 22.4

4) 224

50. The volume of \(0.1 \mathrm{~N}\) dibasic acid sufficient to neutralize \(1 \mathrm{~g}\) of a base that furnishes 0.04 mole of \(\mathrm{OH}-\) in aqueous solution is :

1) \(400 \mathrm{~mL}\)

2) \(600 \mathrm{~mL}\)

3) \(200 \mathrm{~mL}\)

4) \(800 \mathrm{~mL}\)

51. The density of 3M solution of sodium chloride is \(1.252 \mathrm{~g} \mathrm{~mL}^{-1}\). The molality of the solution will be : (molar mass, \(\mathrm{NaCl}=58.5 \mathrm{~g} \mathrm{~mol}^{-1}\) )

1) \(260 \mathrm{~m}\)

2) \(2.18 \mathrm{~m}\)

3) \(2.79 \mathrm{~m}\)

4) \(3.00 \mathrm{~m}\)

52. The amount of \(\mathrm{BaSO}_{4}\) formed upon mixing \(100 \mathrm{~mL}\) of \(20.8 \% \mathrm{BaCl}_{2}\) solution with \(50 \mathrm{~mL}\) of \(9.8 \%\) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) solution with \(50 \mathrm{~mL}\) of \(9.8 \% \mathrm{H}_{2} \mathrm{SO}_{4}\) solution will be: \((\mathrm{Ba}=137, \mathrm{Cl}=35.5, \mathrm{~S}=32, \mathrm{H}=1\) and \(\mathrm{O}=16)\)

1) \(23.3 \mathrm{~g}\)

2) \(11.65 \mathrm{~g}\)

3) \(30.6 \mathrm{~g}\)

4) \(33.2 \mathrm{~g}\)

53. The formula of an acid is \(\mathrm{HXO}_{2}\). The mass of 0.0242 moles of the acid is \(1.657 \mathrm{~g}\). What is the atomic mass of \(X\) ?

1) 35.5

2) 28.1

3) 128

4) 19.0

54. A portable hydrogen generator utilizes the reaction between calcium hydride and water to produce hydrogen. What mass of hydrogen can be produced by 70 g cartridge of calcium hydride ?

1) \(6.7 \mathrm{~g}\)

2) \(3.5 \mathrm{~g}\)

3) \(4.5 \mathrm{~g}\)

4) \(5.5 \mathrm{~g}\)

55. If \(1 \frac{1}{2}\) moles of oxygen combine with \(\mathrm{Al}\) to form \(\mathrm{Al}_{2} \mathrm{O}_{3}\) the weight of \(\mathrm{Al}\) used in the reaction is \((\mathrm{Al}=27)\)

1) \(27 \mathrm{~g}\)

2) \(54 \mathrm{~g}\)

3) \(49.5 \mathrm{~g}\)

4) \(31 \mathrm{~g}\)

56. \(\mathrm{O}_{2}, \mathrm{~N}_{2}\) are present in the ratio of \(1: 4\) by weight. The ratio of number of molecules is :

1) \(7: 32\)

2) \(1: 4\)

3) \(2: 1\)

4) \(4: 1\)

57. \(6.8 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}_{2}\) present in \(100 \mathrm{~mL}\) of its solution. What is the molarity of solution?

1) \(1 \mathrm{M}\)

2) \(2 \mathrm{M}\)

3) \(3 \mathrm{M}\)

4) \(0.5 \mathrm{M}\)

58. How many moles of magnesium phosphate, \(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}\) will contain 0.25 mole of oxygen atoms?

1) \(1.25 \times 10^{-2}\)

2) \(2.5 \times 10^{-2}\)

3) 0.02

4) \(3.125 \times 10^{-2}\)

59. How many moles of \(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\) would be in \(50 \mathrm{~g}\) of the substance ?

1) 0.083 mole

2) 0.952 mole

3) 0.481 mole

4) 0.140 mole

60. \(25 \mathrm{~mL}\) of a solution of barium hydroxide on titration with a 0.1 molar solution of hydrochloric acid gave a litre value of \(35 \mathrm{~mL}\). The molarity of barium hydroxide solution was

1) 0.14

2) 0.28

3) 0.35

4) 0.07

TOPIC 4: Empirical Formula, Molecular Formula and Chemical Stoichiometry 

61. The empirical formula of a compound is \(\mathrm{CH}_{2}\). One mole of this compound has a mass of 42 grams. Its molecular formula is :

1) \(\mathrm{C}_{3} \mathrm{H}_{6}\)

2) \(\mathrm{C}_{3} \mathrm{H}_{8}\)

3) \(\mathrm{CH}_{2}\)

4) \(\mathrm{C}_{2} \mathrm{H}_{2}\)

62. An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71\% and \(\mathrm{H}, 9.67 \%\). The empirical formula of the compound would be :

1) \(\mathrm{CH}_{3} \mathrm{O}\)

2) \(\mathrm{CH}_{2} \mathrm{O}\)

3) \(\mathrm{CHO}\)

4) \(\mathrm{CH}_{4} \mathrm{O}\)

63. In a compound \(\mathrm{C}, \mathrm{H}\) and \(\mathrm{N}\) atoms are present in \(9: 1: 3.5\) by weight. Molecular weight of compound is 108. Molecular formula of compound is

1) \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{~N}_{2}\)

2) \(\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{~N}\)

3) \(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{~N}_{2}\)

4) \(\mathrm{C}_{9} \mathrm{H}_{12} \mathrm{~N}_{3}\)

64. A chloride of a metal \((M)\) contains \(65.5 \%\) of chlorine. \(100 \mathrm{~mL}\) of vapour of the chloride of metal at STP weighs \(0.72 \mathrm{~g}\). The molecular formula of the metal chloride is :

1) \(\mathrm{MCl}\)

2) \(\mathrm{MCl}_{2}\)

3) \(\mathrm{MCl}_{3}\)

4) \(\mathrm{MCl}_{4}\)

65. In the reaction \(4 \mathrm{NH}_{3}(\mathrm{~g})+5 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_{2} \mathrm{O}(\mathrm{l})\) When 1 mole of ammonia and 1 mole of \(\mathrm{O} 2\) are made to react to completion,

1) 1.0 mole of \(\mathrm{H}_{2} \mathrm{O}\) is produced

2) 1.0 mole of NO will be produced

3) all the oxygen will be consumed

4) all the ammonia will be consumed

66. If potassium chlorate is \(80 \%\) pure, then \(48 \mathrm{~g}\) of oxygen would be produced from (atomic mass of \(\mathrm{K}=39\) )

1) \(153.12 \mathrm{~g}\) of \(\mathrm{KClO}_{3}\)

2) \(122.5 \mathrm{~g}\) of \(\mathrm{KClO}_{3}\)

3) \(245 \mathrm{~g}\) of \(\mathrm{KClO}_{3}\)

4) 98 g of \(\mathrm{KClO}_{3}\)

67. The empirical formula of an acid is \(\mathrm{CH}_{2} \mathrm{O}_{2}\), the probable molecular formula of acid may be :

1) \(\mathrm{C} 3 \mathrm{H}_{6} \mathrm{O}_{4}\)

2) \(\mathrm{CH}_{2} \mathrm{O}\)

3) \(\mathrm{CH}_{2} \mathrm{O}_{2}\)

4) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\)

68. Which of the following is the correct empirical and molecular formulae of a compound, if the molecular mass of a compound is 80 and compound contains \(60 \%\) of \(\mathrm{C}, 5 \%\) of \(\mathrm{H}\) and \(35 \%\) of \(\mathrm{N}\) ?

1) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{~N} ; \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{~N}_{2}\)

2) \(\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{~N}_{2} ; \mathrm{C}_{6} \mathrm{H}_{8} \mathrm{~N}_{4}\)

3) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{~N}_{2} ; \mathrm{C}_{4} \mathrm{H}_{8} \mathrm{~N}_{4}\)

4) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{~N} ; \mathrm{C}_{2} \mathrm{H}_{2} \mathrm{~N}\)

69. \(12 \mathrm{gm}\) of \(\mathrm{Mg}\) (atomic mass 24) will react completely with hydrochloric acid to give

1) One mol of \(\mathrm{H}_{2}\)

2) \(1 / 2 \mathrm{~mol}\) of \(\mathrm{H}_{2}\)

3) \(2 / 3 \mathrm{~mol}\) of \(\mathrm{O}_{2}\) 4) both \(1 / 2 \mathrm{~mol}\) of \(\mathrm{H}_{2}\) and \(1 / 2 \mathrm{~mol}\) of \(\mathrm{O}_{2}\)

70. Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator. The number of moles of Mohr's salt required per mole of dichromate is

1) 3

2) 4

3) 5

4) 6