Jamb Chemistry Past Questions And Answers

Jamb Chemistry Past Questions And Answers

Chemistry explores the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances. This subject is popular among science students.

JAMB Chemistry Questions and Answers

Study the following Chemistry past questions and answers for JAMB, WAEC, NECO and Post UTME. Prepare yourself with official past questions and answers for your upcoming examinations.

The Joint Admissions and Matriculation Board Questions and Answers on Chemistry JAMB Chemistry, JAMB Chemistry Questions, JAMB Chemistry Questions 2021, JAMB Chemistry Questions and Answers | Expocoded.com team will be showing you likely JAMB Questions and Answers on Chemistry, JAMB random repeated questions for free.

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You are welcome to 2021 JAMB Chemistry questions and answers. Before we move to Jamb Chemistry question and answer, it is important you know the tricks and what JAMB sets in Chemistry that would help you score high in your Jamb Chemistry examination.

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1 Tricks to answer Jamb Chemistry Questions

2 Jamb Chemistry Practice Question (Expo)

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Tricks to answer Jamb Chemistry Questions

Knowing some constants like mass and the atomic number of elements in chemistry, Avogadro’s number, the mass of the 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.

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Jamb Chemistry Past Questions And Answers

Jamb Chemistry Practice Question (Expo)

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1. What is the shape of a molecule of CCl4?

A. Pyramid

B. tetrahedral

C. Trigonal planar

D. linear

ANSWER: B (Tetrahedral)

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

ANSWER: A (3:1)

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

ANSWER: C (3.6)

4. Which of the following will act as both oxidizing agents 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

ANSWER: C (Silver)

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

ANSWER: B (Degree of disorder of the system)

7. Which of the following is stable to heat


B. ( NH4 )2 SO4

C. Ag NH3

D. K2 CO3

ANSWER: 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

ANSWER: C (Container for caustic soda)

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

ANSWER: D ( Dehydration of the iron )

See: JAMB Chemistry Syllabus

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

ANSWER: A ( I, II and III)

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

ANSWER: A ( 15.0 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

ANSWER: A ( 1.00)

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

ANSWER: D ( Oxygen)

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

ANSWER: A ( metals have very high melting point)

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

A. fertilizer

B. fungicide

C. Disinfectant

D. purifier

ANSWER: B ( fungicide)

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

A. filtered sea water

B. soft drinks

C. flood water

D. writing ink

ANSWER: C ( floodwater)

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

ANSWER: A ( Ethanol)

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






Continue Reading Jamb Chemistry Questions and Answers

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.

ANSWER: A (3 moles of NaOH are required for each mole of glyceride)

21. A piece of radioactive element has initially 8.0×10^22 atoms. The 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

ANSWER: B (5×10^21)

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

A. wet litmus paper

B. printers ink

C. wet pawpaw leaf

D. most wet fabric dyes

ANSWER: B (printers ink)

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

ANSWER: C (it has empty d-orbital)

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

ANSWER: B (3-choropropan-1-ol)

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

ANSWER: 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

ANSWER: 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

ANSWER: C (ethanol)

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

ANSWER: C (form chains which bind molecules together)

29. Complete dehydrogenation of ethyne yields

A. benzene

B. methane

C. ethane

D. propane

ANSWER: 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

ANSWER: D (Barium tetraoxocarbonate)

31. Which of the following conducts electricity?

A. Sulphur

B. Graphite

C. Diamond

D. Red phosphorous

ANSWER: B (graphite)

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)

ANSWER: 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

ANSWER: 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

ANSWER: C ( separates soap from glycerol )

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

A. Lead

B. Heavy water

C. Iron

D. Chromium

ANSWER: B ( heavy water)

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

ANSWER: A ( redox reaction)

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

ANSWER: C ( silver is transition metal)

39. which of these compounds exhibits resonance

A. benzene

B. ethanol

C. propene

D. butyne

ANSWER: A ( Benzene)

40. The oxidation number of oxygen in BaO2 is

A. -2


B. -4


C. -1


D. 0


ANSWER: C ( redox reaction)