Chemistry Past Questions For JAMB/WAEC/NECO Students v4

Chemistry Past Questions For JAMB/WAEC/NECO Students v4; These Chemistry questions are for students who are sitting for the following examinations:

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JAMB
Post-UTME / Post-JAMB
WAEC
NECO
WAEC GCE
NECO GCE
NABTEB
NABTEB GCE

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#1. The size (diameter) of five elements are in the order R < T < W < X < Y, Y being the largest. If each atom has an electron situated on its circumference, and neglecting other factors, which of the atoms will lose its electron most reluctantly? Options

A) R

B) T

C) W

D) X

E) Y

#2. Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

A) P will form an electrovalent bond with R

B) Q will form a covalent bond with S

C) R will form an electrovalent bond with S

D) Q will form an electrovalent bond with S

E) Q will form a covalent bond with R

#3. Which of the following changes is physical?

A) Adding iron filing to aerated water

B) Adding sodium metal to water C) Cooling a solution of Iron (II) sulphate to obtain the hydrated salt

D) Cooling water to obtain ice

Which of the following changes is physical? Options A) Adding iron filing to aerated water B) Adding sodium metal to water C) Cooling a solution of Iron (II) sulphate to obtain the hydrated salt D) Cooling water to obtain ice E) Burning the domestic gas (Utilgas) for cooking

E) Burning the domestic gas (Utilgas) for cooking

#4. A solid X when heated gives off a brown gas. If X is soluble in excess sodium hydroxide solution but insoluble in excess ammonium hydroxide solution, then X is

A) basic lead carbonate

B) lead (II) nitrate

C) sodium carbonate

D) zinc nitrate

E) sodium nitrate

#5. Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100oC, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0oC?

A) X only

B) Y only

C) Z only

D) X and Z

E) Y and Z

#6. An experiment test of the Law of conservation of Mass is illustrated in the diagram. In practice, the flask is weighed before and after reaction between solutions X and Y. Which of the following pairs of solutions will be unsuitable for the experiments

A) X = hydrochloric acid; Y = silver nitrate

B) X = barium chloride; Y = dilute sulphuric acid

C) X = hydrochloric acid; Y = sodium hydroxide

D) X = hydrochloric acid; Y = lead nitrate

E) X = hydrochloric acid; Y = sodium carbonate

#7. Five compounds R,T,W,X and Y form the following compounds: a basic hydride R.H, an acidic hydride YH, atmospheric oxide W2O3, XO2. which of the elements is an alkali

A) R

B) T

C) W

D) X

E) Y

#8. A gas jar was inverted over burning yellow phosphorus floating over water in a beaker. After burning, the water level was found to rise in the gas jar. The water level rises because

A) pressure inside the gas jar is greater than pressure outside it

B) the air in the gas jar had been used up by burning

C) oxygen in the gas jar had been used up by burning

D) nitrogen in the gas jar had been used up by burning

E) the temperature in the jar had risen considerably

#9. You are provided with five gas jars containing SO2, CO2, H2, CO and NO respectively. Select a test from A to E which will identify ANY ONE of the gases completely

A) pass each gas into lime water

B) pass each gas into water and test with litmus paper

C) pass each gas into concentrated sulphuric acid

D) expose each gas to atmospheric air

E) expose each gas to fumes of hydrogen chloride

#10. Which of the following substances would you see as an indicator in the titration of sodium carbonate solution against hydrochloric acid (complete neutralisation)?

A) Litmus paper

B) Phenolphthalein

C) Methyl orange

D) Universal indicator

E) None of these

#11. Which of the following substances would you see as an indicator in the titration of sodium carbonate solution against hydrochloric acid (complete neutralisation)?

A) Litmus paper

B) Phenolphthalein

C) Methyl orange

D) Universal indicator

E) None of these

#12. Consider the following equation H2O + 2Fe2+ + Cl2 ↔ 2Fe3+ + 2Cl- + H2O. The only ion which behaves as an oxidising agent is

A) Fe2+

B) Cl2

C) Fe3+

D) Cl-

E) H2O

#13. If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is

A) dilute sulphuric acid

B) dilute hydrochloric acid

C) unreacted hydrogen sulphide in water

D) iron (III) chloride

E) Iron (II) chloride

#14. By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and

A) potassium nitrate

B) sand

C) lead nitrate

D) sugar (glucose)

E) starch

#15. In titration involving sodium hydroxide and dilute hydrochloric acid, where would you place the base?

A) in the beaker

B) in the conical flask

C) in a burette

D) in the standard flask

E) in the measuring cylinder

#16. The most common type of chemical reaction which alkanes undergo is

A) substitution

B) addition

C) condensation

D) polymerisation

E) double decomposition

#17. Consider the following exothermic reaction 2SO2(g) + O2(g) ↔ 2SO3(g) If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then

A) the reaction rate increases

B) concentration of SO3 decreases

C) concentration of SO3 increases

D) SO2 gas becomes unreactive E) O3 gas becomes unreactive

#18. If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because

A) both zinc and copper are metals

B) the sulphate radical and the zinc ion are divalent

C) zinc is more electropositive than copper

D) both zinc and copper form depositive ions in solution

E) zinc is a reducing agent

#19. Three solutions contain carbonate, sulphate and sulphide ions respectively. One test that will identify just ONE of them completely is by addition to each of them of

A) barium chloride solution

B) dilute hydrochloric acide

C) lead nitrate solution

D) calcium chloride solution

E) sodium hydroxide solution

#20. Two gas cylinders contain ethylene (ethene) and acetylene respectively. One test which can be used to distinguish between them is by Options

A) passing each gas through bromine water

B) passing each gas through dilute potassium permanganate solution

C) passing each gas through silver nitrate solution

D) treating each gas catalytically with excess hydrogen gas

#21. An example of an alcohol is

A) CCl4

B) CH3COOH

C) CHCl3

D) C2H6

E) CH3OH

#22. The nucleus of an atom contains

A) protons only

B) neurons only

C) protons and electrons

D) neutrons and electrons

E) protons and neutrons

#23. Hypochlorous acid is used as a bleach because

A) it is a strong acid

B) it yields chlorine readily in pure water

C) it is an oxidising agent

D) it is a weak acid

E) it is a reducing agent

#24. The normal boiling point of a liquid is defined as

A) the temperature at which its vapour pressure equals the atmospheric pressure

B) the temperature at which bubbles begin to form

C) the temperature at which the vapour pressure equals 1 temperature

D) the temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid

E) the temperature at which the space above the liquid is saturated

#25. Which of the following compounds will form a solution if exposed to air?

A) Na2CO3.10H2O

B) NaNO3

C) CuSO4

D) CaCl2

E) Na2SO4.10H2O

#26. Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys?

A) Tin

B) Zinc

C) Copper

D) Lead

E) Aluminium

#27. Which of the following gases may not be dried with concentrated sulphuric acid?

A) HCl

B) N2

C) Cl2

D) SO2

E) NH3

#28. Which of the following reactions does not take place in the smelting of iron in a blast furnace?

A) CaCO3(s) CaO(s) + CO2(g)

B) C(s) + O2(g) CO2(g)

C) 3FeCO(s) + 2OCO2(g) FeO4(s)

D) SiO2(s) + CaO(s) CaCO3(s)

E) CO2(g) + C(s) 2CO(g)

#29. When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

A) ionic bond

B) electrovalent bond

C) covalent bond

D) co-ordinate bond

E) hydrogen bond

#30. A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by Options

A) boiling the water

B) adding excess calcium hydroxide

C) adding a calculated amount of calcium hydroxide

D) adding sodium carbonate

E) adding magnesium hydroxide

#31. During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,

A) the litmus turns blue but no gas is evolved

B) the litmus turns blue and oxygen is evolved

C) the litmus turns blue and hydrogen is evolved

D) the litmus turns red and oxygen is evolved

E) the litmus turns red and then becomes colourless

#32. The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

A) saponification

B) dehydration

C) esterification

D) hydrolysis

E) hydration

#33. The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;

A) acetic acid and ethane

B) ethanoic acid and ethene

C) methanoic acid and ethylene

D) ethanol and ethene

E) acetic acid and ethylene

#34. If 30cm3 of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm3 of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?

A) 9.3 sec

B) 14 sec

C) 21 sec

D) 28 sec

E) 30.3 sec

#35. When heat is absorbed during a chemical reaction, the reaction is said to be

A) thermodynamic

B) exothermic

C) isothermal

D) endothermic

E) thermostatic

#36. When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as

A) disintegration

B) polymerization

C) cracking

D) degradation

E) distillation

#37. The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore

A) none of these solutions is acidic

B) the pH of Y is made more acidic by addition of distilled water

C) Z is the most acidic solution

D) W is the most acidic solution

E) X is neutral

#38. When each of the nitrates of Potassium, Magnesium and iron is heated,

A) all the nitrates decompose to their oxides

B) the nitrate of magnesium gives the nitrite and oxygen

C) the nitrates of iron magnesium and iron give the oxides

D) the nitrate of iron gives the nitrite and oxygen

E) the nitrate of the magnesium is not decomposed

#39. Which of the following metals cannot replace hydrogen from water or steam?

A) Sodium

B) Magnesium

C) Iron

D) Calcium

E) Copper

#40. A small quantity of solid ammonium chloride (NH4Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

A) distillation

B) sublimation

C) precipitation

D) evaporation

E) decomposition

#41. An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the

A) law of multiple proportions

B) law of chemical proportions

C) law of simple proportions

D) law of conservation of mass

E) law of definite proportions

#42. The oxidation state of chlorine in potassium chlorate is

A) +1

B) +2

C) +3

D) +5

E) +7

#43. When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

A) nitrogen and carbondioxide

B) the rare gases

C) nitrogen and oxygen

D) nitrogen and the rare gases

E) nitrogen, carbondioxide and the rare gases

#44. Zinc Oxide is a

A) Basic Oxide

B) Acidic Oxide

C) Amphoteric Oxide

D) Neutral Oxide

E) Reactive Oxide

#45. When sodium chloride and metallic sodium are each dissolved in water

A) both processes are exothermic

B) both processes are endothermic

C) the dissolution of metallic sodium is endothermic

D) the dissolution of metallic sodium is exothermic

E) the dissolution of sodium chloride is explosive

#46. The periodic classification of elements is an arrangement of the elements in order of their

A) Atomic Weights

B) Isotopic Weights

C) Molecular Weights

D) Atomic Numbers

E) Atomic Masses

#47. In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

A) 5cm3

B) 10cm3

C) 20cm3

D) 25cm3

E) 50cm3

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