2020 Chemistry

1. The electronic configuration of an element is 1S²2S²2P⁶ 3S² 3P³. How many unpaired electrons are there in the element?

• A. 5
• B. 4
• C. 3
• D. 2

2. Which of the following can be obtained by fractional distillation? 

• A. Nitrogen from liquid air
• B. Sodium Chloride from sea water
• C. Iodine from solution of Iodine in carbon tetrachloride
• D. Sulphur from the solution of sulphur in carbon disulphide

3. Duralumin consists of aluminum, copper?

• A. Zinc and Gold
• B. Lead and Manganese
• C. Nickel and Silver
• D. Manganese and Magnesium

4. An example of a polysaccharide is?

• A. Dextrose
• B. Mannose
• C. Glucose
• D. Starch

5. 8g of CH₄occupies 11.2 at S.T.P. What volume would 22g of CH₃CH₂CH₃occupy under the same condition?

• A. 3.7dm³
• B. 11.2dm³
• C. 22.4dm³
• D. 33dm³

6. The best treatment for a student who accidentally poured conc tetraoxosulphate(vi) on his skin in the laboratory is to wash his skin with?

• A. with cool running water
• B. sodium hydroxide solution
• C. iodine solution
• D. sodium trioxonitrate(v) solution

7

Which of the gas laws does this graph illustrate?

• A. Boyle
• B. Charles
• C. Gay-Lussac
• D. Graham

8. What are the possible oxidation numbers of an element if its atomic number is 17?

• A. -1 and 7
• B. -1 and 6
• C. -3 and 5
• D. -2 and 6

9. What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke?

• A. Steam distillation
• B. Destructive distillation
• C. Liquefication
• D. Hydrolysis

10. Liquid black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the ?

• A. Acid
• B. Ester of alkanoic acid
• C. Alkali
• C. Alkanol

11. When water drops are added to calcium carbide in a container and the gas produced is passed through a jet and lighted, the resultant flame is called an?

• A. Oxyethene
• B. Oxyhydrocarbon flame
• C. Oxyacetylene flame
• D. Oxymethane flame

12. Which of the following substances is a mixture?

• A. Granulated sugar
• B. Seawater
• C. Sodium chloride
• D. Iron filling

13. If the quantity of oxygen occupying 2.76L container at a pressure of 0.825 atm and 300k is reduced by one-half, what is the pressure exerted by the remaining gas?

• A. 1.650atm
• B. 0.825atm
• C. 0.413atm
• D. 0.275atm

14. Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

• A. P
• B. Q
• C. R
• D. S

15. The products of the thermal decomposition of ammonium trioxonitrate(v) are?

• A. Nitrogen (I) Oxide and Water
• B. Ammonia and Oxide
• C. Nitrogen and Water
• D. Nitrogen (IV) Oxide and Water

16. How many valence electrons are contained in the element ³¹₁₅P?

• A. 3
• B. 4
• C. 15
• D. 31

17. The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO₃is treated with 0.2dm³of 1 Mole of HCL in the equation

CaCO₃ + 2HCL ⇒ CaCl₂ + H₂O + CO₂, is?

• A. 1.00 X 10²³
• B. 6.02 X 10²³
• C. 6.02 X 10²²
• D. 6.02 X 10²⁴

18. The volume occupied by 1.58g of a gas at S.T.P is 500cm³. What is the relative molecular mass of the gas?  [ G.M.V at S.T.P = 22.4dm³]

• A. 28
• B. 32
• C. 44
• D. 71

19. Which of the following gases will rekindle a brightly splint?

• B. NO₂
• B. NO
• C. N₂O
• D. Cl₂

20. The shape of ammonia molecule is?

• A. Trigonal planar
• B. Octahedral
• C. Square planar
• D. Tetrahedral

21. A few drop of conc HCL are added to about 10cm33 of a solution of PH 3.4. The PH of the resulting mixture is?

• A. less than 3.4
• B. greater than 3.4
• C. unaltered
• D. the same as that of the pure water

22. Chromatography is used to separate components of mixture which differ in their rates of ?

• A. diffusion
• B. migration
• C. reaction
• D. sedimentation

23. Deliquescent substances are also?

• A. efflorescent
• B. anhydrous
• C. hygroscopic
• D. insoluble

24. Helium is used in observation of ballons because it is?

• A. Light and combustible
• B. light and non-combustible
• C. heavy and combustible
• D. heavy and non-combustible

25. 32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm³of water generated 13.0kj of heat. The heat solution is?

• A. 26.0kj/mol
• B. 65.0kj/mol
• C. 130.0kj/mol
• D. 260.0kj/mol

26. A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

[ M = 27, Cl = 35.5]

• A. MCl
• B. MCl22
• C. MCl33
• D. M22Cl66

27. What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

• A. 24,125 C
• B. 48,250 C
• C. 72,375 C
• D. 96,500 C

28. Which of the following types of bonding does not involve the formation of new substances?

• A. Metallic
• B. Covalent
• C. Co-ordinate
• D. Electrovalent

29. An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

• A. Alkene
• B. Alkanal
• C. Alkanone
• D. Alkanoic Acid

30. The substance often used for vulcanization of rubber is?

• A. Chlorine
• B. Hydrogen peroxide
• C. Sulphur
• D. Tetraoxosulphate(vi) acid

31. The chlorinated alkane often used industrially to remove grease is?

• A. Tetrachloromethane
• B. Chloromethane
• C. Trichloromethane
• D. Dichloromethane

32. What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

• A. 8.0g
• B. 16.0g
• C. 36.0g
• D. 72.0g

33. Proteins in acid solution undergo?

• A. Substitution
• B. Fermentation
• C. Hydrolysis
• D. Polymerisation

34. The general formula for the Alkanals is?

• A. R₂CO
• B. RCHO
• C. ROH
• D. RCOOR

35. When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?

• A. Bipolar
• B. Negatively charged
• C. Positively charged
• D. Neutral

36. When a solid substance disappears completely as a gas on heating, the substance is said to have undergone?

• A. Sublimation
• B. Crystallization
• C. Distillation
• D. Evaporation

37. An electron can be added to a halogen atom to form a halide ion with?

• A. 8 valence electrons
• B. 7 valence electrons
• C. 2 valence electrons
• D. 3 valence electrons

38. Aluminum hydroxide is used in the dyeing industry as a?

• A. Dye
• B. Dispersant
• C. Salt
• D. Mordant

39. The most important element on the earth’s crust is?

• A. Nitrogen
• B. Hydrogen
• C. Oxygen
• D. Fluorine

40. To obtain pure carbon(ii)oxide from its mixture with carbon(iv)oxide, the mixture should be?

• A. Passed over heated copper(ii)oxide
• B. Bubbled through water
• C. Bubbled through conc H₂SO₄
• D. Bubbled through conc NaOH