Question bank of Chemistry
1. A balance chemical equation is in accordance with
(a) Avogadro’s law
(b) Law of constant proportion.
(c) Law of conservation of mass
(d) Law of gaseous volumes.
Ans. Law of conservation of mass
2. 4 grams of sodium hydroxide contains (Atomic mass Na = 23 u, O = 16 u, H = 1 u)
(a) 6.023 Х 10 23 atoms of H
(b) 4 grams of Na
(c) 6.023 Х 10 22 atoms of Na
(d) 4 moles of NaOH.
Ans. 6.023 Х 10 22 atoms of Na
3. An example of liquid metal is …………………… and that of liquid non metal is ………………….
Ans. Mercury and Bromine
4. When pentane is burnt in excess oxygen, the products of the reaction are CO2 (g) and H2O (l).
The balanced equation for this combustion is
C5H12(g) + xO2(g) → 5CO2(g) + 6H2O(l)
The coefficient( x) of oxygen should be
(a) 16
(b) 12
(c) 11
(d) 8
Ans. 8
5. The composition of Brass is ………………………
Ans. Copper and zinc
6. The total number of valence electrons in 4.2 grams of N3- ion, is (NA is the Avogadro number)
(a) 1.6 NA
(b) 3.2 NA
(c) 2.4NA
(d) 4.2 NA
Ans. 2.4 NA
7. What would be the number of molecules in 1 litre of water? (molecular weight of H2O = 18 u)
Ans. 55.5Х 6.023Х1023
8. Members of which of the following will have same chemical properties?
(a) Isotopes
(b) Isobars
(c) Allotropes
(d) Both isotopes and allotropes.
Ans. Both isotopes and allotropes
9. The value of e/m of an electron is determined by
(a) Millikan
(b) J.J Thomson
(c) Dalton
Rutherford.
Ans. Millikan
10. Which of the following atoms has valency equal to zero
(a) Hydrogen
(b) Lithium
(c) Neon
(d) Oxygen
Ans. Neon
11. When α- particles are sent through a thin metal foil, most them go straight through the foil
because
(a) α- particles are heavier than electrons
(b) α- particles are positively charged
(c) Most part of the atom is empty space
(d) α- particles move with high velocity.
Ans. Most part of the atom is empty space
12. A proton is identical to
(a) The nucleus of helium
(b) The nucleus of a hydrogen atom
(c) A molecule of a hydrogen
(d) An atom of hydrogen.
Ans. The nucleus of a hydrogen atom
13. The e/m ratio of cathode ray particle of any gas is
(a) Constant (b) zero
(c) less than one
(d) greater than one.
Ans. Constant
14. A natural phenomenon that supports the experimental conclusion that atoms are divisible is
(a) Allotropy (b) radioactivity
(c) cracking
(d) none of these.
Ans. radioactivity
15. For an element with atomic number 19, the 19th electron will occupy
(a) L-shell
(b) M-shell
(c) N-shell
(d) K-shell
Ans. N- shell.
16. The atomic number of an element is determined by
(a)
(b)
(c)
(d)
The number of electrons in an atom
The number of neutrons in an atom
The valency of the element
The number of protons in one atom.
Ans. The number of protons in one atom.
17. The number of electrons in outermost shell of most stable atoms is
(a) 1
(b)4
(c) 6
(d) 8
Ans. 8
18. The relative atomic masses of many elements are not whole numbers because
(a) They cannot be determined very accurately
(b) The atoms ionize during determination
(c) Of the existence of isotopes
(d) Of the presence of impurities.
Ans. Of the existence of isotopes
19. An atom which has a mass number of 14 and has 8 neutrons is an
(a) Isotope of oxygen
(b) Isobar of oxygen
(c) Isotope of carbon
(d) Isobar of oxygen.
Ans. Isotope of carbon
20. Which of the following has equal number of neutrons and protons?
(a) Hydrogen
(b) Deuterium
(c) Fluorine
Ans. Deuterium
21. An α-particle is
(a) A hydrogen molecule
(b) A helium nucleus
(c) An electron
(d) A proton.
Ans. A helium nucleus
22. In electrovalency,
(a) Molecules lose electrons forming atoms
(b) Molecules gain electrons forming atoms
(c) Atoms share electrons
(d) Atoms lose or gain electrons forming ions.
(d)Chlorine
Ans. Atoms lose or gain electrons forming ions
23. Noble gases exist as individual
(a) Atoms
(b) ions
(c) molecules
(d) compounds
Ans. Atoms.
24. Which of the following can lose two electrons to attain the configuration of Argon?
(a) Mg
(b) Br
(c) S
(d) Ca
Ans. Mg.
25. Electropositive atoms tend to form
(a) Negative ions
(b) positive ions
(c) covalent bonds
(d) metallic bond.
Ans. positive ions
26. Which of the following molecules contains a triple bond?
(a) CCl4
(b) C2H4
(c) C2H2
(d) NH3
Ans. C2H2
27. Molten sodium chloride conducts the electricity due to the presence of
(a) Free electrons
(b) free ions
(c) free molecules
(d) atoms of Na and Cl.
Ans. free ions
28.
(a)
(b)
(c)
(d)
Which of the following statement is wrong?
An atom is electrically neutral
The size of a cation is smaller than that of corresponding atom
The size of the anion is bigger than that of corresponding atom
An atom and its ion have unequal number of protons.
Ans. An atom and its ion have unequal number of protons.
29. The total number of electrons that take part in bond formation in N2
(a) 2
(b) 4
(c) 6
(d) 8
Ans. 6
30. Which of the following bond is non directional?
(a) Co-valent (b) electrovalent
(c) co-ordinate covalent bond
Ans. electrovalent
31. Metallurgy is a process of
(a) Extracting metal from its mineral
(b) Extracting metal from its ore
(d) none of these.
(c) Extracting pure metal from its ore
(d) Extracting metal from its pure ore.
Ans. Extracting pure metal from its ore
32. Aluminium is used in thermite welding because
(a) Aluminium is a light metal
(b) Aluminium has more affinity for oxygen
(c) Aluminium is a strong oxidizing agent
(d) Aluminium is a reactive metal.
Ans. Aluminium is a reactive metal.
33. Copper does not react with dilute HCl but reacts with in the presence of air or oxygen because
(a) Copper is ranked lower than hydrogen in activity series.
(b) HCl is not an oxidizing agent
(c) Air or Oxygen oxidizes the copper metal to Cu+2 ion
(d) All of these.
Ans. Copper is ranked lower than hydrogen in activity series.
34. Which of the following is liquid at ordinary temperature?
(a) Germanium
(b) Gallium
(c) Gold
(d) Galena
Ans. Gallium
35. When non-metal reacts with oxygen, they form
(a) Amphoteric oxide
(b) Acidic oxide
(c) Basic oxide
(d) None of these.
Ans. Acidic oxide
36. Which of the following elements is not present in stainless steel?
(a) Iron
(b) Tungsten (c) Chromium (d) Nickel
Ans. Tungsten
37. Which of the following is not an ore of aluminium?
(a) Cryolite
(b) Feldspar
(c) Bauxite
(d) Azurite
Ans. Feldspar
38. A solution reacts with crushed eggshells to give a gas that turns lime water milky, the solution
contains
(a) NaCl
(b) HCl
(c) KCl
(d) LiCl
Ans. HCl
39. When zinc metal reacts with dilute sodium hydroxide, the gas evolved
(a) Supports combination
(c) Turns lime water milky
(b) Burns with pop sound
(d) has pungent odour.
Ans. Burns with pop sound
40. When a cleaned iron nail is dipped in a solution of substance ‘X’ a reddish brown material
deposited on it. Substance ‘X’ is
(a) Ferrous Sulphate (b) Zinc sulphate
(c) Ferric Chloride
(d) Copper sulphate.
Ans. Copper sulphate.
41. If tartaric acid is not added to baking powder, the cake will taste bitter due to the presence of
(a) Sodium hydrogen carbonate
(b) carbon dioxide
(c) Sodium carbonate
(d) All of these.
Ans. Sodium carbonate
42. Aqueous solution of which of the following salts turns the red litmus blue?
(a) Na2CO3
(b) NaHCO3
(c) Na2CO3.10 H2O
(d) All.
Ans. All
43. The substance which on treating with chlorine, yields bleaching powder is
(a) Quick lime (b) Slaked lime (c) Limestone (d) Gypsum.
Ans. Slaked lime
44. Soda-acid fire extinguisher extinguishes the fire
(a) By cutting the supply of air
(b) By removing combustible substance
(c) By raising the ignition temperature
(d) None of these.
Ans. By cutting the supply of air
45. In which of the following pair, both the substances are chemically same?
(a) Milk of lime and lime water
(b) Dead burnt plaster and gypsum
(c) Alumina and gypsum
(d) Gypsum and plaster of paris.
Ans. Milk of lime and lime water
46. The property of an to form a bond with itself is known as
(a) Isomerism (b) catenation (c) allotropy
(d) none of these.
Ans. Catenation.
47. The gas used I the welding and cutting of metals is
(a) Ethane
(b) ethene
(c) ethyne
(d) propane.
Ans. Ethyne.
48. The alkaline hydrolysis of oil or fat gives soap and
(a) Glycerol
(b) Ethanol
(c) Glycol
(d) ethanoic acid.
Ans. Glycerol.
49. Formalin is 40% solution
(a) Methanol (b) methanal
(c) methanoic acid
(d) none of these.
Ans. Methanol.
50. The enzyme used in the conversion of fructose into ethanol is
(a) Zymase
(b) invertase (c) diastase
(d) fructose.
Ans. Zymase.
51. Which of the following elements will form basic oxide? An element with atomic number→
(a) 7
(b) 17
(c) 14
(d) 11
Ans. 11
52. The group number and period number respectively of an element with atomic number 8 is
(a) 6,2
(b) 16, 2
(c) 6, 8
(d) 16, 4
Ans. 6, 2
53. In third period of modern periodic table element having smallest size is
(a) Na
(b) Ar
(c) Cl
(d) Si
Ans. Ar
54. Which of the following set does not belong to a group
(a) Li, Na, K
(b) B, C, N
(c) B, Al, Ga
(d) O, S, Se
Ans. B, C, N
55. The two elements for which the Mendeleev left gaps in his periodic table are
(a) Bi, Ge
(b) Al, Ga
(c) Na, K
(d) Ga, Ge.
Ans. Ga, Ge
56. Who proposed the atomic number of an element is more fundamental property than its atomic
mass?
(a) Lavoisier
(b) Dobereiner
(c) Newland
(d) Moseley
Ans. Moseley
57. The number of valence shell of an atom indicate
(a) The group to which an element belongs
(b) The period to which an elements belongs
(c) The reactivity of an element
(d) All of these.
Ans. The period to which an elements belongs
58. Elements in the same group have
(a) Same electropositivity
(b) Same valence electrons
(c) Same number of shells
(d) Same atomic size.
Ans. Same valence electrons
59. The elements belonging to 17th group of the periodic table are collectively termed as
(a) Halogens
(b) Alkali metals
(c) Alkaline earth metals
(d) Noble gas.
Ans. Halogens
60. An element belonging to group 14 and second period of the periodic table exhibits the following
set of properties
(a) Solid and moderately metallic
(b) Solid and non metallic
(c) Solid and most metallic
(d) Liquid and highly metallic.
Ans. Solid and non metallic
61. The isomeric pair is
(a) Ethane and propane
(b) Propane and butane
(c) Ethane and ethane
(d) Butane and 2-methyl propane.
Ans. Butane and 2-methyl propane.
62. Which of the following is used to oxidise ethanol to ethanoic acid?
(a) Alkaline KMnO4
(b) Conc. H2SO4
(c) Acidified K2Cl2O7
(d) All of above.
Ans. Alkaline KMnO4
63. Identify the product formed when methane reacts with chlorine in the presence of sunlight is
(a) C2Cl6
(b) CH3Cl
(c) CHCl4
(d) None of these.
Ans. CH3Cl
64. The compound which gives brisk effervescence with sodium metal and not with sodium
hydrogen carbonate is
(a) Ethanol
(b) Ethanoic acid
(c) Both ethanoic acid and ethanol
(d) None of these.
Ans. Ethanol
65. The substance not responsible for hardness of water is
(a) Calcium nitrate
(b) Calcium hydrogen carbonate
(c) Calcium carbonate
(d) Magnesium carbonate.
Ans. Calcium hydrogen carbonate
66. Which amongst the following is a unsaturated hydrocarbon?
(a) Cyclobutane
(b) Propane
(c) Propyne
(d) Hexane.
Ans. Propyne.
67. Which is not true about members of homologous series?
(a) They have same general formula
(b) They differ from each other by CH2 group
(c) They have same physical properties
(d) They have same functional group.
Ans. They have same physical properties
68. The number of single and double bond present in benzene are
(a) 9 and 6
(b) 9 and 3
(c) 12 and 3
(d) 12 and 6
Ans. 12 and 3
69. Which of the following can be used for denaturation of ethanol?
(a) Methyl alcohols
(b) Pyridines (c) Copper sulphate
(d) All of the above .
Ans. All of the above .
70. Covalent compounds are
(a) Have high melting and boiling points
(b) Are mostly soluble in water
(c) Are formed between atoms of metal and non metals
(d) Are formed by sharing of electrons in the bonding atoms.
Ans. Are formed by sharing of electrons in the bonding atoms.
71. An element ‘A’ is soft and can be with knife. It is stored in kerosene oil because it catches fire in
the presence of moisture. It imparts yellow colour to the flame. The element is
(a) P
(b) I
(c) Na
(d) Ca
Ans. Na
72. Silver articles become black on prolonged exposure to air. This is due to formation of
(a) Ag3N
(b) Ag2S
(c) Ag2O
(d) Ag2SO3
Ans. Ag2S
73. The composition of aqua regia is
(a) Dil.HCl + conc.HNO3 in ratio of 3:1
(b) Dil.HCl + dil.HNO3 in ratio of 3:1
(c) Conc.HCl + conc.HNO3 in ratio of 3:1
(d) Conc.HCl + dil.HNO3 in ratio of 3:1
Ans. Conc.HCl + conc.HNO3 in ratio of 3:1
74. Which of the following properties is not shown by ionic compounds?
(a) Solubility in water
(b) Electrical conductivity in solid state
(c) High melting and boiling point
(d) Electric conductivity in aqueous solution and in molten state.
Ans. Electrical conductivity in solid state
75. Which of the following metals exist in their native state in nature?
(a) Ca
(b) Au
(c) Ag
(d) both b and c
Ans. both b and c
76. Bronze is a
(a) Homogeneous mixture of Cu and Sn
(b) Compound of Cu and Sn
(c) Heterogeneous mixture of Cu and Sn
(d) Homogeneous mixture of Cu and Zn.
Ans. Homogeneous mixture of Cu and Zn.
77. Galvanization is a method of protecting iron from rusting by coating with thin layer of
(a) Magnesium
(b) Zinc
(c) Chromium (d) Aluminium.
Ans. Zinc
78. During electrolytic refining of copper it gets deposited on
(a) it gets deposited on cathode
(b) It gets deposited on anode
(c) It gets deposited on both cathode and anode
(d) It remains in the solution.
Ans. it gets deposited on cathode
79. Which of the non- metal is in liquid state?
(a) Carbon
(b) Bromine
(c) Chlorine
(d) Iodine.
Ans. Bromine.
80. Which of the following will form amphoteric oxide?
(a) Al
(b) Cu
(c) Zn
(d) Both a and c.
Ans. Both a and c.
81. When a solid is dispersed in liquid to form a colloidal solution, it is called:
(a) Sol
(b) Gel
(c) Aerosol
(d) None of these.
Ans. Sol.
82. A student was given crystals of copper sulphate to be dissolved in water. She observed that the
solution is:
(a) Clear and transparent
(b) Turbid
(c) Blue in colour and clear
(d) Milky.
Ans. Blue in colour and clear
83. Sulphur is soluble in :
(a) Water
(b) Alcohol
(c) Carbon disulphide
(d) None of these.
Ans. Carbon disulphide.
84. The separation technique which involves difference in densities of components of a mixture is
(a) Sublimation
(b) Separation by separating funnel
(c) Centrifugation
(d) Both (b) and (c)
Ans. Both (b) and (c)
85. Tyndall effect is shown by:
(a) Milk
(b) Sugar solution
(c) Salt solution
(d) All of these.
Ans. Milk
86. 50 gram sugar is dissolved in a glass of at 30oC. On heating this solution it will
(a) Crystallize
(b) Evaporate
(c) Become unsaturated
(d) Sugar will char.
Ans. Become unsaturated.
87. Which one of the following sets of phenomena would decrease with decrease in temperature?
(a) Diffusion, evaporation, solubility of a gas in liquid.
(b) Evaporation, diffusion, expansion of gases.
(c) Diffusion, solubility of solid in liquid, compression of gases
(d) Evaporation, solubility of gas in liquids, diffusion, expansion of gases.
Ans. Evaporation, solubility of gas in liquids, diffusion, expansion of gases.
88. A gas can be liquefied at
(a) Low temperature, low pressure
(b) High temperature, high pressure
(c) Low temperature, high pressure
(d) High temperature, low pressure.
Ans. Low temperature, high pressure
89. During summers water kept in earthen pots becomes cool because of phenomenon of
(a) Evaporation
(b) transpiration
(c) effusion
(d) osmosis.
Ans. Evaporation.
90. The heat energy required to convert 1 kg water into steam at 100oC is called
(a) Latent heat
(b) Latent heat of vaporization
(c) Molar heat of fusion
(d) None of these.
Ans. Latent heat of vaporization
91. As the pressure of air decreases, the boiling point of the liquid
(a) Decreases (b) increases (c) Does not changes (d) None of these.
Ans. Decreases
92. The rate of diffusion is slowest in
(a) Solid
(b) Liquid
(c) Gas
Ans. Solid.
93. Evaporation of a liquid occurs at
(a) Boiling point
(b) At fixed temperatures
(c) At temperatures lower than boiling point
(d) At all temperature.
Ans. At temperatures lower than boiling point
94. Which of the following is chemical change
(a) Explosion of dynamite
(b) Sublimation of iodine
(c) Melting of sodium in nuclear reactor
(d) Condensation of steam.
(d) None of these.
Ans. Explosion of dynamite
95. Kerosene oil and water can be separated by
(a) Separating funnel
(b) Distillation
(c) Centrifugation
(d) Evaporation.
Ans. Separating funnel
96. Acetone and water can be separated by
(a) Distillation
(b) Steam distillation
(c) Evaporation
(d) Separating funnel
Ans. Distillation.
97. 1 carat diamond is
(a) 200 g
(b) 200 mg
(c) 20 mg
(d) 2 g
Ans: 200 mg
98. Which of the following is a compound?
(a) Stainless steel
(b) Brass
(c) Iron sulphide
Ans: Iron sulphide.
99. The lowest possible attainable temperature is
(a) -273.15 oC
(b) 0 oC
(c) -100 oC
Ans: -273.15 oC
100.
(a) 9
The atomicity of K2Cr2O7 is
(b) 11
(c) 12
Ans: 11
(d) 10.
(d) Diamond
(d) -270 oC