HYDROGEN MCQs – 2

1) Which one of the following metals will not reduce H2O ?
a) Ca
b) Fe
c) Cu
d) Li

2) Which one of the following is reduced by H2O2 in acid solution ?
a)
b) KI
c)
d)

3) D2O is used more in
a) the chemical industry
b) Nuclear reactors
c) Pharmaceutical preparations
d) Insecticide preparations

4) Which of the following is correct for hydrogen?
a) It can form bonds in +1 as well as in -1 oxidation state
b) It is collected at the cathode
c) It has a very high ionisation potential
d) All of these

5) A sample of hard water was found to contain 68 ppm of CaSO4 and 19 ppm of MgCl2. Its total hardness is
a) 70 ppm
b) 50 ppm
c) 20 ppm
d) 100 ppm

6) A@ Which of the following statements is correct ?
a)
b)
c)
d) All are correct

7) The weight percentage of D2 in heavy water is
a) 22
b) 11.11
c) 4
d) 20

8) Protium, deuterium and tritium
a) Are isotopes of hydrogen
b) Have similar chemical properties
c) Have their atomic masses in the ratio of 1 : 2 : 3
d) All are correct

9) The ortho and para hydrogen have the
a) Same physical properties but different chemical properties
b) same chemical properties but different physical properties
c) Same chemical and physical properties
d) Different physical and chemical properties

10) Heavy water is obtained by
a) the evaporation of water
b) Keeping water in nuclear reactors
c) Prolonged electrolysis of ordinary water
d) adding impurities to ordinary water

11) Para hydrogen is
a) Less stable than ortho hydrogen
b) More stable than ortho hydrogen
c) As stable as ortho hydrogen
d) None

12) Name the metal which liberates H2 gas when reacted with either acid or NaOH
a) Fe
b) Zn
c) Cu
d) None

13) Hydrogen peroxide is not used
a) As a reducing agent
b) As an oxidising agent
c) As a dehydrating agent
d) As a bleaching agent

14) The bleaching action of H2O2 is due to
a) Reduction
b) Oxidation
c) Decomposition of colouring matter
d) None

15) Heavy water freezes at
a)
b)
c)
d)

16) The decomposition of H2O2 is retarded by
a) Acetanilide
b) Manganese oxide
c) Zinc
d) Finely divided metals

17) The volume of O2 gas liberated at STP by the decomposition of 15 mL of 20 volume H2O2 solution is
a) 150 mL
b) 300 mL
c) 200 mL
d) 250 mL

18) On shaking H2O2 with acidified potassium dichromate and ether, the etherial layer becomes
a) Green
b) Blue
c) Red
d) Colourless

19) A substance gives off O2 when heated, turns an acid solution of KI violet, and reduces acidified KMnO4. The substance is
a)
b)
c)
d) All of these

20) A sample of water contains 111 ppm of CaCl2. The hardness of that water sample is
a) 111
b) 50
c) 100
d) 555

21) Activated hydrogen is obtained by
a) Electrolysis of heavy water
b) Reaction of water with heavy metals
c) Thermal decomposition of water
d) Passing silent electric discharge through hydrogen at low pressure

22) The degree of hardness is defined as the number of parts by weight of CaCO3 or its equivalent present in
a) A million parts by weight of water
b) A thousand parts by weight of water
c) A hundred parts by weight of water
d) Ten million parts by weight of water

23) Which of the following is not used as a water softener for permanent hardness ?
a) NaOH
b)
c)
d) Sodium hexametaphosphate

24) In which of the following reactions is H2O2 acting as a reducing agent?
a)
b)
c)
d)

25) H2O2 is stored in a/ an
a) Iron container after addition of stabilizer
b) Glass container after addition of stabilizer
c) Plastic container after addition of stabilizer
d) None of these

26) Which of the following is not present in clear hard water?
a)
b)
c)
d)

27) H can be placed in VII A group because
a) H is light
b) H contains one electron only
c) It forms hydrides like NaH
d) It has isotopes D and T

28) Hydrogen is not obtained when zinc reacts with
a) Cold water
b)
c) Dilute HCl
d) Hot 20% NaOH

29) Permanent hardness of water can be removed by
a) Ion exchange resins
b) Permutit
c) Lime soda process
d) All are correct

30) In the case of H2O2 the O-O bond length is
a)
b)
c)
d)

31) Hydrogen does not combine with
a) Sb
b) Na
c) Bi
d) He

32) H2O2 converts potassium ferrocyanide to ferricyanide. The following change is observed in the oxidation state of iron:
a)
b)
c)
d)

33) Titanium salts give the following colour with H202:
a) Violet
b) Blue
c) Yellow
d) Orange Red

34) The metal that can displace hydrogen from boiling NaOH solution is
a) As
b) Zn
c) Mg
d) Fe

35) Which of the following does not cause hardness of water ?
a)
b)
c)
d)

36) The oxidising property of H2O2 is best explained by assuming that the two oxygen atoms in its molecule are
a) Bonded differently
b) Bonded similarly
c) Bonded covalently
d) Bonded by hydrogen bonds

37) When the same amount of Zn is treated separately with excess of H2SO4 and excess of NaOH solution, the ratio of the volume of H2 evolved is
a) 1 : 1
b) 1 : 2
c) 2 : 1
d) 9 : 4

38) The hydrogen produced in contact with the substance to be reduced is known as
a) Ordinary hydrogen
b) Nascent hydrogen
c) Atomic hydrogen
d) Heavy hydrogen

39) Permanent hardness of water is due to the presence of
a)
b)
c) Ca, Mg sulphates and chlorides
d) None

40) The most reactive state of hydrogen is
a) Atomic hydrogen
b) Heavy hydrogen
c) Molecular hydrogen
d) Nascent hydrogen

41) Hydrogen resembles both halogens and alkali metals in that
a)
b)
c)
d) All the above

42) The decomposition of H2O2 is accelerated by
a) Glycerine
b) Alcohol
c) Phosphoric acid
d) Pt powder

43) Which of the following liberates hydrogen when treated with HNO3 ?
a) Ag
b) Cu
c) Mg
d) Hg

44) Reactions between the following pairs will produce hydrogen except
a) Cu + HCl
b)
c) Mg + Steam
d) Na + Alcohol

45) H2O2 acts as an oxidising agent in
a) Acidic as well as alkaline medium
b) Neutral medium
c) Acidic medium only
d) Alkaline medium only

46) In the reaction between CuO and H2, the hydrogen
a) Is reduced
b) Is a catalyst
c) Loses electrons
d) Acts as an oxidising agent

47) When H2O2 is treated with chlorine
a)
b)
c) Hypochlorous acid is formed
d)

48) The catalyst used in the Bosch process of manufacture of H2 is
a) Finely divided Ni
b)
c) Pd
d)

49) Which is the poorest reducing agent ?
a) Hydrogen
b) Nascent hydrogen
c) Atomic hydrogen
d) All have the same reducing strength

50) In which of the following reactions H2O2 is not acting as an oxidising agent ?
a)
b)
c)
d)

51) H2O2 reduces K3 [Fe(CN)6] in
a) Neutral solution
b) Acidic solution
c) Alkaline solution
d) Non-polar medium

52) Hydrogen can reduce
a)
b)
c)
d) All of these

53) An ionic compound is dissolved simultaneously in heavy water and ordinary water, its solubility is
a) Larger is heavy water
b) Smaller in heavy water
c) Solubility is same in both waters
d) Smaller is simple water

54) Which of the following statements regarding H2O2 is wrong ?
a) It is stable in acid medium
b) It acts as oxidising as well as reducing agent
c) It has zero dipole moment
d)

55) H2O2 acts as an antiseptic due to its
a) Reducing property
b) Oxidising property
c) Bleaching property
d) Acidic property

56) All the following substances react with water. The pair that yields the same gaseous product is
a)
b)
c)
d)

57) On boiling temporary hard water may produce
a)
b)
c)
d)

58) In H2O2 the proton (H+) exists as
a)
b)
c)
d) All the above

59) A mixture of hydrazine (N2H4) and 58 – 60% solution of H2O2 is used as
a) Antiseptic
b) Fertilizer
c) Rocket fuel
d) None

60) Deliquescent substances are also called
a) Hygroscopic
b) Metamorphic
c) Polymorphic
d) None

61) An example of a salt-like hydride is
a)
b)
c)
d)

62) The pH values of D2O and H2O at 25°C are
a) 7, 7
b) 7.35, 7
c) 7, 6.85
d) 6.85, 7.35

63) Heavy water is not used for drinking because
a) It is poisonous
b) It is costly
c) Its physiological action is different from ordinary water
d) Its chemical properties are different from ordinary water

64) In acid medium, H2O2 acts as an oxidising agent in its reaction with
a)
b)
c)
d)

65) The hardness of water
a)
b)
c) Is estimated by titration with EDTA
d) All of the above

66) The substance which reduces the speed of decomposition of H2O2 is
a)
b) NaOH
c) Alcohol
d) Pt

67) Hydrogen has three isotopes. The number of possible diatomic molecules will be
a) 2
b) 6
c) 9
d) 12

68) H2O2 is
a) Diamagnetic
b) Paramagnetic
c) Ferromagnetic
d) None of these

69) In the reaction of ozone and H2O2 the latter acts as a/an
a) Oxidising agent
b) Reducing agent
c) Bleaching agent
d) Both oxidising and reducing agent

70) The bond energy of the covalent O -H bond in water is
a) Equal to the bond energy of the hydrogen bond
b) Greater than the bond energy of the hydrogen bond
c) Less than the bond energy of the hydrogen bond
d) None

71) H2O2 is used as
a) An oxidant
b) A reductant only
c) An acid only
d) An oxidant, reductant and acid

72) Ortho and para hydrogen are similar in the property of
a) Thermal conductivity
b) Magnetic property
c) Chemical reactions
d) Heat capacity

73) When different metals like Zn, Sn, Fe are added to dilute sulphuric acid, the same gas, which burns explosively in air, is evolved. The gas is
a)
b)
c)
d)

74) Ozone reacts with H2O2 to give oxygen. One volume of ozone gives
a) One volume of oxygen
b) Half volume of oxygen
c) 1.5 volume of oxygen
d) Two volumes of oxygen

75) 10 volumes of H2O2 is a solution with a strength of approximately
a) 3%
b) 30%
c) 10%
d) 5%

76) Hydrogen may directly combine with
a) Mg
b) Cu
c) Ni
d) Ca

77) For making H2O2 in a laboratory
a)
b)
c)
d)

78) The percentage of para hydrogen in ordinary hydrogen increases when the
a) Temperature is lowered
b) Temperature is increased
c) Pressure is increased and the temperature is decreased
d) None

79) The conversion of ordinary hydrogen into atomic hydrogen is
a) Nuclear reaction
b) An endothermic reaction
c) An exothermic reaction
d) A decomposition reaction

80) Which of the following is a true peroxide?
a)
b)
c)
d)

81) Hydrogen acts as an oxidising agent in its reaction with
a)
b)
c) Na
d) S

82) The shape of the H2O2 molecule is
a) Tetrahedron
b) Pyramidal
c)
d) Square planar

83) The negative catalyst for the decomposition of H2O2 is
a)
b) Dil. NaOH
c) Glycerol
d) Powdered Ag

84) The hybridisation of the orbitals of oxygen in H2O2 is
a)
b) sp
c)
d)

85) The number of protons, electrons and neutrons in a molecule of heavy water is respectively
a) 10, 10, 10
b) 8, 10, 11
c) 10, 11, 10
d) 11, 10, 10

86) The ionisation of the hydrogen atom gives a/an
a) Hydride ion
b) Hydronium ion
c) Proton
d) Hydroxyl ion

87) Which of the following hydrides is the most powerful reducing agent?
a) HF
b) LiH
c)
d)

88) When a molten ionic hydride is electrolysed
a)
b)
c)
d)

89) In an H2O2 molecule
a) Two hydrogen atoms are connected to one of the oxygen atoms
b) All the four atoms are in the same plane
c) The four atoms are arranged in a non-linear and non-planar manner
d) None

90) Commercially H2O2 is now prepared by
a)
b)
c)
d) By burning hydrogen in excess of oxygen

91) A given solution of H2O2 is 30 volume. Its concentration in terms of molarity is
a) 9.1 M
b) 2.65M
c) 2.5 M
d) 26.8 M

92) In the presence of finely divided Ni, hydrogen reacts with vegetable oils. The process is known as
a) Halogenation
b) Hydrogenation
c) Occlusion
d) Oxidation

93) At absolute zero
a) Only para hydrogen exists
b) Only ortho hydrogen exists
c) Both para and ortho hydrogen exist
d) None of these

94) Which of the following statements is correct ?
a) Deuterium has two electrons
b) Deuterium has two protons
c) Deuterium has the same mass as that of hydrogen
d) Deuterium has the same atomic number as that of hydrogen

95) The approximate mass of tritium oxide is
a) 18 amu
b) 20 amu
c) 22 amu
d) 24 amu

96) Which of the following solutes will produce temporary hardness in water ?
a)
b)
c) NaCl
d)

97) H2O2 is
a) a poorer polar solvent than water
b) a better polar solvent than water
c) Both have the same polarity
d) A better polar solvent but its strong oxidising property limits its use as such

98) H2O2 is commonly prepared in the laboratory by the reaction
a)
b)
c)
d)

99) Which of the following is used to sterilise water ?
a)
b)
c)
d)

100) The salt responsible for the permanent hardness of water is
a)
b)
c)
d) NaCl


Answer

Ans 1) c

Ans Desc 1) Because Cu lies below hydrogen in the electrochemical series.

Ans 2) a

Ans Desc 2) H2O2 decolourises KMnO4.

2KMnO4+ 3H2SO4+ 5H2O2 ® 2MnSO4+ K2SO4+ 8H2O+ 5O2.

Ans 3) b

Ans Desc 3) is used as a moderator in atomic reactors.

Ans 4) d

Ans Desc 4) Nil

Ans 5) a

Ans Desc 5) 136 ppm CaSO4= 100ppmCaCO3 = 95 ppm MgCl2.

Thus 68 ppm CaS04 = 100 x 68/ 136 = 50 ppm CaCO3.

19 ppm = 100 x 19/95 = 20 ppm CaCO3.

Total hardness = 50 + 20 = 70 ppm.

Ans 6) d

Ans Desc 6) Nil

Ans 7) d

Ans Desc 7)

Ans 8) d

Ans Desc 8) Nil

Ans 9) b

Ans Desc 9) Ortho and para hydrogens have different physical properties but the same chemical properties.

Ans 10) c

Ans Desc 10) Nil

Ans 11) a

Ans Desc 11) Ortho form is more stable.

Ans 12) b

Ans Desc 12) Zn+ 2NaOH® Na2ZnO2+ H2

Zn+ H2SO4® ZnSO4+ H2

Ans 13) c

Ans Desc 13) H2O2 is not used as a dehydrating agent.

Ans 14) b

Ans Desc 14) Bleaching action is due to oxidation, H2O2 ® H2O + [O].

Ans 15) b

Ans Desc 15) Heavy water freezes at a slightly higher temperature (3.80C) than ordinary water.

Ans 16) a

Ans Desc 16) Acetanilide acts as a negative catalyst.

Ans 17) b

Ans Desc 17) 1 mL of 20 volume H2O2 solution liberates 20 mL O2 at STP.

Thus 15 mL will liberate 20 x 15 = 300 mL O2 at STP.

Ans 18) b

Ans Desc 18) The etherial layer becomes blue, which is stabilised by ether.

Cr+ 2H+ + 2H2O2® CrO5+ 3H2O.

Ans 19) c

Ans Desc 19) These are the properties of H2O2.

Ans 20) c

Ans Desc 20) 111 ppm CaCl2 = 100 ppm CaCO3. Thus the hardness of the water sample is 111 x 100 /111 = 100 ppm.

Ans 21) d

Ans Desc 21)

Ans 22) a

Ans Desc 22) Degree of hardness is the number of parts by weight of CaCO3 or its equivalent in a million parts by weight of water.

Ans 23) b

Ans Desc 23) All except, Ca(OH)2 are used as water softeners.

Ans 24) d

Ans Desc 24) Ag2O is reduced to Ag.

Ans 25) c

Ans Desc 25) Nil

Ans 26) d

Ans Desc 26) The hardness is not due to MgCO3.

Ans 27) c

Ans Desc 27) Hydrogen accepts one electron and forms hydride ion, which has the noble gas configuration Is2. Halogens in VII group also accept one electron and form ion, which also have noble gas configuration

Ans 28) a

Ans Desc 28) H2 is not given out when zinc reacts with cold water, because zinc is not as electropositive as alkali and alkaline earth metals are.

Ans 29) d

Ans Desc 29) Permanent hardness can be removed by all these methods.

Ans 30) b

Ans Desc 30) Nil

Ans 31) d

Ans Desc 31) Because He is an inert gas.

Ans 32) a

Ans Desc 32) H2O2 oxidises Fe2+ ion to ion.

Ans 33) d

Ans Desc 33) Due to the formation of pertitinic acid. Ti(SO4)2 + H2O2 + 2H2O ® H2TiO4 + 2H2SO4

Ans 34) b

Ans Desc 34) Zn + 2NaOH + 2H2O ® Na2 [Zn(OH)4]+ H2

Ans 35) c

Ans Desc 35)

Ans 36) a

Ans Desc 36) It is believed that out of two hydrogens, one is associated with each oxygen atom at a bond angle of 97°. All the four atoms H-O-O-H do not lie in the same plane.

Ans 37) a

Ans Desc 37) H2SO4+ Zn® ZnSO4 + H2

2NaOH + Zn ® Na2ZnO2 + H2.

In each case volume of H2 evolved is one.

Ans 38) b

Ans Desc 38) + [H] ® + HCl, when granulated zinc is added into an acidified solution of FeCl3, it is reduced to FeCl2 by the nascent hydrogen.

Ans 39) c

Ans Desc 39) Permanent hardness is due to sulphates and chlorides of Ca and Mg.

Ans 40) d

Ans Desc 40)

Ans 41) d

Ans Desc 41) These are characteristics of hydrogen.

Ans 42) d

Ans Desc 42) Decomposition of H2O2 can be accelerated by finely divided metals such as Ag, Au, Pt, Co, Fe etc.

Ans 43) c

Ans Desc 43) Because Mg is above hydrogen in the electrochemical series.

Ans 44) a

Ans Desc 44) Because Cu is below hydrogen in the electrochemical series.

Ans 45) a

Ans Desc 45) H2O2 acts as oxidising agent in acidic and alkaline medium.

H2O2 + 2H+ + ® 2H2O (acid medium).

H2O2 + ® 2OH(basic medium).

Ans 46) c

Ans Desc 46) In the reaction CuO+ H2 ® Cu+ H2O hydrogen is acting as reducing agent.

It is reducing Cu2+ to Cu as, Cu2+ + 2e ® Cu.

Ans 47) b

Ans Desc 47) H2O2+ Cl2® 2HCL+ O2.

Ans 48) d

Ans Desc 48) In the Bosch process Fe2O3 + Cr2O3 is used as a catalyst.

Ans 49) a

Ans Desc 49) Because H2 is less reactive than atomic and nascent hydrogen.

Ans 50) d

Ans Desc 50) In the reaction Ag2O + H2O2 ® 2Ag + O2 + H2O,

H2O2 is acting as a reducing agent and reduces moist silver oxide to Ag.

Ans 51) c

Ans Desc 51) + H2O2 + 2OH®

2 [Fe(CN)6]4-+ 2H2O+ O2.

Ans 52) d

Ans Desc 52) Hydrogen can reduce all, because Au, Ag and Cu lie below hydrogen in the

electrochemical series.

Ans 53) b

Ans Desc 53) Solubility of ionic compounds is less in heavy water.

Ans 54) c

Ans Desc 54) H2O2 is a polar compound and its dipole moment is not zero. It is stable in acid medium because adding small amounts of acid can retard its decomposition. It also acts as oxidising and reducing agent. Pure H2O2 is slightly acidic, because its aqueous solution is slightly or weakly acidic.

Ans 55) b

Ans Desc 55) H2O2 acts as an antiseptic because it kills bacteria by oxidation. It gives off nascent oxygen which kills bacteria.

H2O2 ® H2O + [O].

Ans 56) b

Ans Desc 56) Ca + 2H2O® Ca(OH)2 + H2

CaH2+ 2H2O® Ca(OH)2+ H2

Ans 57) a

Ans Desc 57) Ca(HCO3)2® CaCO3+ CO2+ H2O

Ans 58) d

Ans Desc 58) H+ ion exists as H3O+, or as in an aqueous solution of H2O2.

H202+ H2O® H3O++

Ans 59) c

Ans Desc 59) A mixture of H2O2 and hydrazine (N2H4) is used as a rocket fuel.

Ans 60) a

Ans Desc 60)

Ans 61) a

Ans Desc 61)

Ans 62) b

Ans Desc 62) The pH value of heavy water is slightly higher than that of pure water.

Ans 63) c

Ans Desc 63) Because its physiological action is different from ordinary water.

Ans 64) b

Ans Desc 64) In acid solution H2O2 liberates I2 from KI solution.

2KI + 2H2SO4 ® K2SO4+ 2H2O + .

Ans 65) d

Ans Desc 65) All methods can be used for determining the hardness, which is generally expressed as ppm of CaCO3.

Ans 66) c

Ans Desc 66) Decomposition of H2O2 can be retarded by adding alcohol.

Ans 67) b

Ans Desc 67) These are H1H1, H2H2, H3H3, H1H2, H2H3 and H1H3 .

Ans 68) a

Ans Desc 68) It does not have unpaired electrons.

Ans 69) b

Ans Desc 69) In presence of strong oxidising agents like O3 (oxidation potential = 20.7 V), the H2O2 acts as a reducing agent. Because both H2O2 and O3 act as oxidising as well as reducing agent, in such cases the substance acts as an oxidising or a reducing agent depending on the conditions of the reaction and the nature of other reactants. If the other reactant is a more powerful oxidising agent (such as O3) the former (such as H2O2) behaves as a reducing agent. If the other reactant is a comparatively weak oxidising agent, the reactant in question behaves as an oxidising agent.

Ans 70) b

Ans Desc 70) The bond energy of the covalent O-H bond in water is greater than the bond energy of the hydrogen bond, because a covalent bond is stronger than a hydrogen bond.

Ans 71) d

Ans Desc 71) H2O2 acts as oxidant, reductant and as an acid.

Ans 72) c

Ans Desc 72) Because of the same atomic number, they are expected to show similar chemical properties.

Ans 73) d

Ans Desc 73) Zn + dil.H2SO4 ® ZnSO4 + H2

Sn+ dil.H2SO4® SnSO4+ H2

Fe + dil. H2SO4 ® FeSO4 + H2

Ans 74) d

Ans Desc 74) H2O2 + O3® 2O2+ H2O.

Ans 75) a

Ans Desc 75) % conc.of H2O2 = 17 x vol. Conc.of H2O2 / 56 = 17 x 10 / 56 = 3% approx.

Ans 76) d

Ans Desc 76) Ca+ H2® CaH2

Ans 77) b

Ans Desc 77) BaO2+ CO2+ H2O ® H2O2 + BaCO3

Ans 78) a

Ans Desc 78) The percentage of the para form increases as the temperature is decreased.

Ans 79) b

Ans Desc 79) The atomic hydrogen is very reactive and readily combines with another atom to produce H2 molecule. This reaction is exothermic and a large amount of heat is liberated in the process 2H ® H2+ 101,000 cals. The reverse reaction H2 ® 2H, will therefore be endothermic. Moreover, bond formation is always exothermic.

Ans 80) b

Ans Desc 80) Na2O2 contains peroxide linkage (O-O linkage) while this linkage is not present in NO2, MnO2 and PbO2.

Ans 81) c

Ans Desc 81) In its reaction with Na, it oxidises Na to Na+ (Na loses one electron).

Ans 82) c

Ans Desc 82) H2O2 molecule has open book shape with 90° angle.

Ans 83) c

Ans Desc 83) Glycerol acts as a negative catalyst for the decomposition of H2O2.

Ans 84) d

Ans Desc 84) In H2O2, oxygen is sp3 hybridised

Ans 85) a

Ans Desc 85) Heavy water is D2O. D has 1 electron, 1 proton and 1 neutron. O has 8 electrons, 8 protons and 8 neutrons. Thus D2O has 10 electrons, 10 protons and 10 neutrons.

Ans 86) c

Ans Desc 86) H-e® H+ (Proton).

Ans 87) b

Ans Desc 87) LiH is the most powerful reducing agent among these.

Ans 88) c

Ans Desc 88) Ionic hydrides are generally formed by alkali and alkaline earth metals which are more electropositive than hydrogen.

Ans 89) c

Ans Desc 89) In H2O2, the 4 atoms (H-O-O-H) are arranged in a non-linear and non-planar manner.

Ans 90) c

Ans Desc 90) Commercially H2O2 is prepared by electrolysis of 50% sulphuric acid.

Ans 91) b

Ans Desc 91) Percentage strength of 10 vol. H2O2 = 3 g.

Thus 100 mL of 30 vol.

H2O2 contain 3×3 = 9.0 g.

Molarity =

Ans 92) b

Ans Desc 92) The process is called hydrogenation. Here nickel acts as a catalyst.

Ans 93) a

Ans Desc 93) The % of the para form increases if the temperature is lowered and at absolute zero only the para form, having the lowest internal energy, exists.

Ans 94) d

Ans Desc 94) Deuterium has the same atomic number as that of hydrogen, because both are isotopes.

Ans 95) c

Ans Desc 95) 31H2O= 2×3+ 16 = 22amu.

Ans 96) b

Ans Desc 96)

Ans 97) d

Ans Desc 97) In pure state the dielectric constant of H2O2 is 93.7 which is greater than that of water (80), the dielectric constant increases further with dilution. The high dielectric constant can weaken the electrostatic forces of attraction among ions and so H2O2 is a better polar solvent than water for ionic compounds, but it is not used as such because it undergoes auto oxidation rapidly.

Ans 98) c

Ans Desc 98) BaO2+ H2O+ CO2® H2O2+ BaCO3

Ans 99) b

Ans Desc 99)

Ans 100) a

Ans Desc 100)

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