Tuesday, 19 March 2019

NDA PAST QUESTIONS ON CHEMISTRY 2014


1. Which of the following molecules has two lone pairs of electrons and is SP3
A. NH3
B. C6H6
C. H2O
D. CO2


2. Calculate the concentration of OH- ion (in moles per dm3) present in a solution of PH 4.398
A. 4.0x 10-5
B. 2.5 x 10-10
C. 4.0x 10-9
D. 4.4 x 1014

3. Steam changes the colour of hydrous cobalt (II) chloride from____
A. blue to pink
B. white to blue
C. white to red
D. blue to white

4. The electronic configuration of excited carbon atom is
A. 1S2 2S2 2Px1 2Py1
B. 1S2 2S1 2Px1 2Py1 2P21
C. 1S2 2S2 2P2
D. 1S2 2S1 2P4

5. The oxidation number of carbons is carbon disulphide (CS2) is the same as that of sulphur in
A. S
B. H2S
C. S8
D. H2SO4

6. For the reaction:
2H + Zn H2 + Zn2+
DG = -147KJ mol. What is the corresponding value of E0 cell?
A. 1.52 V
B. -0.76 V
C. 0.76 V
D. -1.52 V

7. Electrolysis is applied in the following process except
A. electroplating
B. extraction of aluminium
C. extraction of iron
D. purification of copper

8. Which of the following compounds would NOT give a precipitate with ammonia and AgNO3 solution?
A. C4C3 = CCH3
B. HC = CH
C. CH3C = C4
D. CH3 CH C2 = CH

9. Which of the following substances causes the depletion of the ozone layer in the atmosphere?
A. Carbon (IV) oxide
B. Chlorofluorocarbon
C. Sulphur (V) oxide
D. hydrocarbons

10. The Hydronium ion is___
A. H+
B. HO-
C. H2+
D. H3O+

11. 10 cm3 of CO is mixed and sparked with 100 cm3 of air containing 21% oxygen, O2. If all the volume are measured at STP, the resulting gases would be_____
A. 90 cm3
B. 100 cm3
C. 105 cm3
D. 110 cm3

12. An element X has 127 neutrons and 82 electrons; its atomic number is_____
A. 209
B. 82
C. 105
D. 127

13. In which of the following processes is iron being oxidized?
I. Fe + H2SO4 FeSO4 + H2
II. FeSO4 + H2S FeS + H2SO4
III. 2FeCl2 + Cl2 2FeCl3
IV. 2FeCl3 + SnCl2 2FeCl2 + SnCl4
A. 1 and 3
B. 1 only
C. 2 and 4
D. 3 only

14. Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed and removed by
A. Heating the affected parts in order to boil off the petroleum
B. Pouring organic solvents to dissolve the petroleum
C. Cooling to freeze out the petroleum
D. Spraying water with detergents

15. The first metal used by man was____
A. Iron
B. Bronze
C. Gold
D. Copper

16. Which kind of bonding can be found in a sample of H2O(l)?
A. Hydrogen bond only
B. non-polar covalent bonds only
C. ionic and non-polar hydrogen bonds
D. Both polar covalent and hydrogen bonds

17. The electronic configuration of an element X is 1s2 2s2 2p6 3s2 3p4. It can be deduced that X____
A. belongs to Group VI of Periodic Table
B. belongs to Period IV of the Periodic Table
C. has 3 unpaired electrons in its atom
D. has a relative molecular mass of lb

18. The order in which a mixture of sand, ammonium chloride and sodium chloride can be separated is____
A. Sublimation dissolution filtration evaporation
B. dissolution dryness filtration —, evaporation
C. Filtration sublimation evaporation dryness
D. dissolution filtration sublimation evaporation

19. Smoke consists of____
A. solid particles dispersed in liquid
B. solid or liquid particles dispersed in gas
C. gas or liquid particles dispersed in liquid
D. liquid particles dispersed in liquid

20. CO(g) + ½ O2(g) CO2(g), DH = -285kLmol-1
What is the energy change in kJmol-1 for the reaction given above?
[DH(CO) = -110.4kJmol-1; DH(CO2) = 393kJmol-1]
A. +503.4 kJmol-1
B. -503.4 kJmol-1
C. +393.0 kJmol-1
D. -282.6 kJmol-1


What is the reaction given above?
A. α- decay
B. β- decay
C. γ- decay
D. None of the above

22. The electronic configuration of Mg2+ ion is____
A. 1s2 2s2 2p5
B. 1s2 2s2 2p6
C. 1s2 2s2 2p4
D. 1s2 2s2 2p3

23. Natural Silicon in silicon-containing ores contains 92% Silicon-28, 5% Silicon-29 and 3% Silicon-30. What is the relative atomic mass of Silicon?
A. 28.11
B. 28.53
C. 28.92
D. 28.3

24. X has an empirical formula C2H2 and relative molecular mass 58. X is___
A. Ethane
B. Propane
C. Butane
D. Hexane

25. The following are methods of preparing bases except
A. Burning metal in air
B. Decomposition of carbonates or hydroxides by heating
C. Dissolving the basic oxide in water
D. Action of water or steam on non-metals

26. The alkenes form a homologous series of saturated hydrocarbons. They have a general molecular formula of___
A. CnH2n
B. CnH2n+1
C. CnH2n+2
D. CnH3n+2

27. Which of the following contain carbon that is SP hybridized?
A. Propene
B. Propane
C. Propyne
D. Propanol

28. The noble gases (Group 0) of the Periodic Table have filled
A. S — subshells
B. S and P — subshells
C. P and d subshells
D. S, P, d, f subshells

29. The heat change associated with a given chemical change is always constant and is independent with time and of any intermediate changes involved. This is
A. Dalton's Law of Heat Summation
B. Hess's Law of Heat Summation
C. Dulon & Petil Law of Heat Summation
D. Born-Haber Law of Heat Summation

30. In carbon atom, the wave functions for the respective electrons can be represented thus
A. 1 (S + Px + Py + Pz)
B. 1 (S + Px - Py - Pz)
C. S (Px - Py + Py - Pz)
D. 1 (S - Px - Py + Pz)

31. The formula CH2O for ethanoic acid is regarded as its____
A. empirical formula
B. molecular formula
C. structural formula
D. general formula

32. Which of the following gases contains the least number of atom at s.t.p?
A. 7 moles of argon
B. 4 moles of chlorine
C. 3 moles of ozone
D. 1 mole of butane

33. Which of the following substances is not a homogenous mixture?
A. Filtered seawater
B. Soft drink
C. Flood water
D. Writing ink

34. Which of the following gases dissolves in water vapour to produce acid rain during rainfall?
A. Oxygen
B. Carbon (II) oxide
C. Nitrogen
D. Sulphur (IV) oxide

35. A sample of Orange juice is found to have a pH of 3.80. What is the concentration of the hydroxide ion in the juice?
A. 1.6 × 10-4
B. 6.3 × 10-11
C. 6.3 × 10-4
D. 1.6 × 10-11

36. Despite of the electronic configuration 1s22s2p2, carbon is tetravalent because
A. the electrons in both 2s and 2p orbitals have equal energy
B. the electrons in both 2s and 2p orbitals are equivalent
C. both the 2s and 2p orbitals have equal energy
D. the six orbitals hybridize to four

37. Which of the following compounds will give a precipitate with an aqueous ammoniacal solution of copper (I) chloride?
A. CH3CH = CHCH3
B. CH3 C = C CH3
C. C HC = C — CH2CH3
D. CH2 = CH — CH = CH2

38. The efficiency of petrol as a fuel in high-compression combustion engines improves with an increase in the amount of ____
A. branched chain alkanes
B. straight chain alkanes
C. cycloalkanes
D. halogenated hydrocarbons

39. A palm wine seller stocked a bottle of his palm wine in his stall and after a few hours, the bottle exploded. Which of the following equation represents the enzyme's reaction that occurred?
A. C6H12O 2C2H5OH + 2CO + 2CO2(g)
B. C2H5OH CH2 = CH2(s) + H2O
C. C2H5OH + dil H2SO C2H5O SO2OH
D. 2C6H12O6 C12H2O13 + H2O solid with a

40. Ethanol reacts with aqueous sodium mono oxoiodide(I) to give a bright yellow solid with a characteristics smell; the product is
A.  trichloromethane
B. triiodomethane
C. iodoethane
D. ethanol

ANSWERS:
1. C
2. B
3. A
4. B
5. C
6. C
7. C
8. A
9. B
10. D
11. A
12. B
13. A
14. B
15. D
16. D
17. A
18. A
19. B
20. D
21. A
22. B
23. A
24. C
25. D
26. A
27. C
28. D
29. B
30. A
31. C
32. A
33. C
34. D
35. B
36. C
37. C
38. A
39. A

40. B