SSS One Chemistry OBJ Exams Questions

SSS One objective questions in Chemistry

1. What is the percentage composition of Sulphur in Sulphur(IV)oxide,SO₂? (S=32, O=16).
A. 66%
B. 25%
C. 40%
D. 50%
2. If the difference in electronegativity of elements P and Q is 30, the bond that will be formed between them is?
A. metallic
B. covalent
C. co-ordinate
D. Ionic
3. The oxidation number of boron in NaBH₄ is?
A. -3
B. -1
C. +1
D. +3
4. The difference between colloid and suspension is brought about out clearly by the fact that while colloids
A. do not scatter light, suspension do
B. can be separated by filtration, suspension cannot be separated
C. can be separated by membrane, suspension cannot
D. do not settle out on standing, suspension do
5. How many protons, neutrons and electrons respectively are present in the element ⁶⁰₂₇𝐶O ?
A. 27, 33 and 33
B. 33, 27 and 27
C. 27, 33 and 27
D.60, 33 and 60
6. A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180. Find the molecular formula. (H=1, C=12, O=16)
A. CH₂O
B. C₃H₆O₃
C. C₆H₁₂O₆
D. C₆H₁₂O₃
7. A compound contains 31.9% potassium, 28.93%, Chlorine and the rest oxygen. What is the chemical formula of the compound (K=39, Cl=35.5, O=16)
A. KClO
B. KClO₂
C. KClO₄
D. KClO₃
8. The oxidation state of oxygen on tetraoxosulphate(IV)acid, ion SO₄^2- is
A. -4
B. -2
C. 4
D. -8
9. Chlorine consisting of two isotopes of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotope of mass number 37.
A. 20
B. 25
C. 60
D. 75
10. NH₃(g) + HCl(s) = NH₄Cl(s). the entropy change in the system above is
A. positive
B. zero
C. negative
D. intermediate
11. The difference between chemical and physical change is that in a chemical change
A. oxygen is consumed
B. heat is supplied
C. the reversiblr process occurs
D. new substance is formed.
12. Diffusion is slowest in solid particles than in particles of liquid and because
A. solid particles have more kinetic energy than the particles of liquid and gases
B. solid particles have less kinetic energy than the particles of liquid and gases
C. solid particles have less restriction in their movement than liquid and gas particle
D. the particles in solids are far apart and the cohesive force between them are negligible
13. A mixture is different from a compound because
A. the properties of a compound are those of its individual constituents while those of a mixture differ from its individual constituents.
B. a mixture is always homogeneous while a compound is not.
C. the constituents of a compound are chemically bond together while those of a mixture are not
D. a mixture can be represented by a chemical formula while a compound cannot.
14. The dispersion of a liquid in a liquid medium will give
A. an emulsion
B. a fog
C. a gel
D. an aerosol.
15. The bond formed between two elements 1S² 2S² 2P⁶ 3S² and 1S² 2S² 2P⁴
A. metallic
B. covalent
C. dative
D. ionic
16. How many unpaired electrons are in the p- orbitals of fluorine atom?
A. 3
B. 0
C. 1
D. 2
17. Which of the following molecules is held together by hydrogen bon
D.
A. CH₄H₂SO₄
B. HBr
C. H₂SO₄
D. HF
18. The solvent used for removing stain is
A. turpentine
B. ammonia solution
C. ethanol
D. solution of borax and water.
19. The constituent of air that acts as a diluent is
A. nitrogen
B. carbon (IV)
C. noble gases
D. oxygen.
20. If the element X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form.
A. dative bond
B. covalent
C. ionic
D. metallic.
21. A hydrogen atom which has lost an electron contains
A.one proton only.
B. one neutron
C. one proton and one neutron
D. one proton, one electron and one neutron.
22. An increase in entropy can best be illustrated by
A. mixing of gases
B. freezing of water
C. the condensation of vapour
D. solidifying candle wax.
23. The electronic configuration of Mg²⁺ is
A. 1S² 2S² 2P⁶ 3S² 3P²
B. 1S² 2S² 2P⁶ 3S²
C. 1S² 2S² 2P⁶
D. 1S² 2S² 2P⁴ .
24. A suitable solvent for iodine and naphthalene is
A. carbon (IV) sulphide
B. ethanol
C. water
D. benzene.
25. An isotope has an atomic number of 15 and a mass number of 31. The number of protons it contains is
A. 16
B. 15
C. 46
D. 31.
26. The maximum number of electrons in the L- shell of an atom is
A.2
B. 8
C. 18
D. 32.
27. Which of the following is an example of a mixture?
A. common salt
B. blood
C. sand
D. washing soda.
28. The IUPAC nomenclature of the compound LiAlH4is
A.lithium tetrahydridoaluminate (III)
B. aluminium tetrahydridolithium
C. tetrahydrido lithium aluminate (III)
D. lithium aluminate hydride.
29. Which of the following is a physical change
A. freezing ice cream
B. dissolving calcium in water?
C. burning kerosene
D. exposing white phosphorus to air.
30. If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
A. naturally radioactive
B. abundant in nature
C. a transition metal.
D. an isotopic mixture.
31. P total = P1 + P2 + P3 +…………..Pn, where P total is the pressure of a mixture of gases. The equation above is an expression of
A. Graham’s law
B. Gay- Lussac’s law
C. Boyle’s law
D. Dalton’s law
32. If 1.0dm3 of gas diffuses through a porous plug in 60 seconds while the same volume of hydrogen diffuses in 15 seconds under the same condition, calculate the relative molecular mass of X(H=1.0)
A. 4.0
B. 8.0
C. 16
D. 32
33. Which of the following compounds is covalent
A. CaCl₂
B. MgO
C. NaCl
D. CH₄
34. Which of the following statements about dative bonding is not correct
A. there is sharing of electrons
B. an atom must possess a lone pair of electron
C. each participating atom contributes one electron
D. it can be formed between molecules
35. What type of bond will be formed between element P and Q if their electronegativity values are 0.8 and 4.0 respectively?
A. covalent bonding
B. co-ordinate bond
C. ionic bond
D. metallic bond
36. What type of chemical bonding is involved in the formation of NH₄⁺ from molecule of ammonia and a proton?
A. covalent bonding
B. co-ordinate covalent bonding
C. electrovalent bonding
D. hydrogen bonding
37. When sodium form the ion Na⁺ ,
A. it gains one electron
B. it gains one proton
C. it achieves a noble gas configuration
D. its atomic number increases
38. If the difference between electronegativities of two elements is large, the type of bond that can be formed between them is
A. covalent
B. dative
C. ionic
D. metallic
39. Which of the following species does not contain a co-ordinate bond?
A. Al₂Cl₆
B. CCl₄
C. H₃O⁺
D. NH₄⁺
40. Which of the following compounds has hydrogen bonds between its molecules?
A. HF
B. HBr
C. HCl
D. HI
41. A mixture of kerosene and diesel oil can be separated by
A. crystallization
B. distillation
C. precipitation
D. sublimation
42. What is the value of -14^oC on the Kelvin temperature scale?
A. 259k
B. 259^ok
C. 287k
D. 287^ok
43. The separation of petroleum fractions depends on the differences in their
A. Boiling point
B. molar masses
C. melting points
D. solubilities
44. Which type of bond is represented by the dotted lines in the following structure?

A. covalent bond
B. dative bond
C. ionic bond
D. hydrogen bond
45. Given that r is rate and P is density, the expression r ∝ 1/√𝑃 represents
A. Boyle’s law
B. Charles’ law
C. Dalton’s law
D. Graham’s law
46. The advantage of detergent over soap is that detergents
A. are readily available
B. are in powdered form
C. are non-biodegradable
D. lather readily with water
47. The initial volume of a gas 300k was 220cm³. Determine its temperature if the volume became 250cm³.
A. 183k
B. 264k
C. 300k
D. 341k
48. Noble gas molecule are held by
A. van der waals forces
B. hydrogen bonds
C. dative bonds
D. covalent bonds
49. Which of the following phenomena leads to decrease in volume of a liquid in an open container?
A. Brownian motion
B. diffusion
C. evaporation
D. sublimation
50. The pressure exerted by a gas is a function of the
A. total volume of the gas
B. speed of the gaseous molecule
C. mass of each gaseous molecule
D. frequency of collision between gaseous molecules
51. The following set-up can be used to demonstrate

A. Diffusion
B. dissolution
C. evaporation
D. sublimation
52. The general gas equation was derived from
A. Boyle’s and Gay Lussac’s laws
B. Boyle’s and Graham’s laws
C. Boyle’s and Charles’ laws
D. Dalton’s atomic theory
53. Which of the following does not take place in domestic water treatment?
A. chlorination
B. flocculation
C. neutralization
D. sedimentation
54. The spreading of the scent of a flower in a garden is an example of
A. Brownian motion
B. diffusion
C. osmosis
D. tyndall effect
55. Pipe-borne water is usually chlorinated in order to
A. improve the taste of the water
B. remove the hardness in the water
C. kill harmful bacteria in the water
D. make the water clear and colourless
56. What type of bond is indicated by the arrow in the following structure?

A. covalent
B. ionic bond
C. dative bond
D. hydrogen bond
57. A substance is said to be impure if
A. its melting point range is wide
B. it dissolves in water with difficulty
C. it has a low melting point
D. it is coloured
58. An arrange drink concentrate is suspected to contain traces of poisonous green dye and a harmless dye having the same boiling point. Which of the following techniques is most suitable for isolating the dyes?
A. fractional distillation
B. paper chromatography
C. coagulation
D. recrystallization
59. In countries where the temperature and pressure falls below 273k, salt is always sprinkled on the icy roads in order to
A. lower the melting point of ice
B. increase the density of ice
C. make the ice impure
D. raise the melting point of ice
60. Which method of separation does the following diagram illustrate?

A. Filtration
B. evaporation
C. sublimation
D. magnetization