Chemistry 2020 Past Questions | JAMB

Study the following Chemistry past questions and answers for JAMBWAEC  NECO and Post-JAMB. Get prepared with official past questions and answers for upcoming examinations.

  1. The electronic configuration of an element is 1S2 2S2 2P6 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 CH44 occupies 11.2 at S.T.P. What volume would 22g of CH3CH2CH3 occupy 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

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