Jamb Chemistry Questions and Answers for 2020 (CBT)

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2020 Jamb Chemistry Questions and Answers

You are welcome to 2020 JAMB Chemistry questions and answers. Before we move to Jamb Chemistry question and answer, it is important you know the tricks that would help you score high in your Jamb Chemistry.

The secret to passing any exam is intensive study. That said, getting a high score in Jamb is what every Jamb candidate desires but some candidate’s expectations do not come into reality.

Tricks to answer Jamb Chemistry Questions

Knowing some constants like mass and atomic number of elements in chemistry, Avogadro’s number, the mass of proton, neutron and electron, speed of light e.t.c will help you to answer some bonus questions asked by Jamb without giving some constants.

It is also important to note some popular principles and laws in chemistry as most of them would form part of the question you will see in your Jamb Chemistry questions.

Due to no time or lack of it, let’s quickly move to 2020 Jamb Chemistry questions and answers.

Jamb Chemistry Practice Question

1. What is the shape a molecule o CCl4?

A. Pyramid

B. tetrahedral

C. Trigonal planar

D. linear

2. A sample of gas with an initial volume of 2.5 dm3 is heated and then allowed to expand to 7.5 dm3 at constant at pressure. What is the ratio of the final temperature of the initial absolute temperature?

A. 3:1

B. 1:3

C. 2:5

D. 5:2

3. 6g of Mg was to 100cm3 of 1 moldm3 H2 SO4 . What mass of Mg remained undissolved? (Mg = 24)

A. 0.24g

B. 2.4g

C. 3.6g

D. 0.36g

4. Which of the following will act as both oxidizing agent and reducing agents?

A. H2 S

B. NH3

C. Cl2

D. SO2

5. A metal which can be used as sacrificial anode for preventing corrosion of length of iron pipe is

A. copper

B. magnesium

C. silver

D. lead

6. Which of the following increases as boiling water changes to steam?

A. Temperature of the system

B. degree of disorder of the system

C. number of molecule

D. Activation energy

7. Which of the following is stable to heat


B. ( NH4 )2 SO4

C. Ag NH3

D. K2 CO3

8. Which of the following will precipitate in dil. HCl

A. ZnS

B. Na2 S

C. Fe S

D. CuS

9. Which of the following does NOT contain aluminum as a component?

A. Over-head cables

B. Duralumin

C. Container for caustic soda

D. Container for trioxonitrate (v) acid

10. The removal of rust from iron by treatment with tetraoxosulphate (vi) acid is based on the

A. Hydrolysis of the iron

B. Reaction of acid with base

C. Oxidation of the rust

D. Dehydration of the iron

11. Which of the following constitutes a mixture? I. Petroleum II. Rubber latex III. Vulcanizer’s solution IV. Carbon (iv) sulphide

A. I, II and III

B. I, II and IV

C. I and II only

D. I and IV

12. 30 cm3 of oxygen at 10 atmosphere pressure is placed in a 20 dm3 container. Calculate the new pressure if the temperature is kept constant.

A. 6.7 atm

B. 15.0 atm

C. 6.0 atm

D. 66.0 atm

13. A sample of gas exerts a pressure of 8.2 atm when confined in a 2.93 dm3 container at 20c. The number of moles of gas in the sample is

A. 1. 00

B. 2.00

C. 3.00

D. 4.00

14. A quantity of air passed through a weighted amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of

A. nitrogen

B. neon

C. argon

D. oxygen

15. There is a large temperature interval between the melting point and the boiling point of a metal because:

A. metals have a very high melting point

B. metals conduct heat very rapidly

C. melting does not break the metallic bond but boiling does

D. the crystal lattice of metal is easily broken

16. Copper (II) tetraoxosulphate (IV) is widely used as

A. fertilizer

B. fungicide

C. Disinfectant

D. purifier

17. Which of the following substances is not a homogeneous mixture?

A. filtered sea water

B. soft drinks

C. flood water

D. writing ink

18. Ethene, when passed into concentrated H2SO4, is rapidly absorbed. The product is diluted with water and then warmed to produce

A. Ethanol

B. diethyl ether

C. ethanal

D. diethyl sulphate

19. A certain liquid has a high boiling point. It is viscous, non-toxic, and miscible with water to be hygroscopic; this liquid most likely to be





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20. Which of the following statement is TRUE of the complete hydrolysis of a glyceride by sodium hydroxide?

A. 3 moles of NaOH are required for each mole of glyceride

B. 3 moles of glycerol are produced

C. only one mole of soap is formed

D. concentrated H2SO4 is essential for the completion of the reaction.

21. A piece of radioactive element has initially 8.0×10^22 atoms. Half life of two days after 16 days the number of atom is

A. 5×10^21

B. 5×10^22

C. 25×10^21

D. 25×10^22

22. Chlorine is a common bleaching agent. This is not true with

A. wet litmus paper

B. printer’es ink

C. wet pawpaw leaf

D. most wet fabric dyes

23. Calcium forms complexes with ammonia because

A. it is a transition metal

B. it is an s-block element

C. it has empty d-orbital

D. it forms colourless compounds

24. The IUPAC name for CICH2-CH2-CH2-OH is

A. 1-chloropropan-3-ol

B. 3-chloropropan-1-ol

C. 1 cholorpropano

D. 3-chloropropanol

25. An organic compound decolourized acidified KMnO4 solution but failed to react with ammonical AgNO3 solution. The organic compound is likely?

A. a carboxylic acid

B. Alkane

C. Alkene

D. Alkyne

26. A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature?

A. 18.6K

B. 100.0K

C. 298.0K

D. 4768.0K

27. The boiling point of water, ethanol, toulene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively, which liquid has the highest vapour pressure at 323.0k

A. water

B. toluene

C. ethanol

D. butan-2-ol

28. The function of sulphur during the vulcanization of rubber is to

A. act as a catalyst for the polymerization of rubber molecules

B. convert rubber from thermosetting to thermoplastic polymer

C. form chains which bind rubber molecules together

D. break down rubber polymer molecules

29. Complete dehydrogenation of ethyne yields

A. benzene

B. methane

C. ethane

D. propane

30. Mixing aqueos solution of barium hydroxide and sodium tetraoxocarbonate (iv) yields a white precipitate of

A. Barium oxide

B. Sodium tetraoxocarbonate

C. Sodium hydroxide

D. Barium tetraoxocarbonate

31. Which of the following conducts electricity?

A. Sulphur

B. Graphite

C. Diamond

D. Red phosphorous

32. Which of the following compound is NOT the correct formed compound when the parent metal is heated in air?

A. Calcium oxide

B. Sodium oxide ( Na2O )

C. Copper (II) oxide (CuO)

D. tri-iron tetraoxide (Fe2O)

33. When marble is heated to 1473K, another whiter solid is obtained which reacts vigoriously with water to give an alkaline solution. The solution contains



C. Mg(OH)2

D. Ca(OH)2

34. Which of the following roles does sodium chloride play in preparation? It

A. reacts with glycerol

B. purifies the soap, accelerates the decomposition of fat and oil

C. separates soap from glycerol

D. converts the fat acid to its sodium salt

35. Which of the following is used as a moderator to control nuclear fission?

A. Lead

B. Heavy water

C. Iron

D. Chromium

36. One of the active components of baking powder is

A. MgSO4


C. CaSO4

D. NaCl

37. H2SO4 is used to remove rust on the surface of iron (picking) before electroplating. The type of reaction involved is

A. redox reaction

B. Neutralization

C. Double decomposition

D. Hydrolysis

38. Silver chloride turns gray when exposed to sunlight because

A. the silver ion is reduced to silver

B. the silver io is oxidized to silver

C. silver is transition metal

D. the silver chloride forms complexes in the sun

39. which of these compounds exhibits resonance

A. benzene

B. ethanol

C. propene

D. butyne

40. The oxidation number of oxygen in BaO2 is

A. -2

B. -4

C. -1

D. 0

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