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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

1,623 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

1,623 questions
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Question 1 of 20 1,623 total questions
Question 581
waec 2000

When sodium hydroxide solution is added to a solution of zinc salt, the white precipitate formed re-dissolves in excess sodium hydroxide because

Asodium is more reactive than zinc
Bsodium hydroxide is a strong alkali
Czinc hydroxide is amphoteric
Dzinc hydroxide is unstable
View Explanation & Discuss
Question 582
waec 2000

A colourless, odourless liquid T, gives effervescence with sodium trioxocarbonate (IV) and a white precipitate with silver trioxonitrate (V) solution T is most probably

Asodium chloride solution
Bbarium chloride solution
Cdilute trioxonitrate (V) acid
Ddilute hydrochloric acid
View Explanation & Discuss
Question 583
waec 2000

Two-organic substances are labelled K and L if K gave a blue-black colour with iodine solution and L gave a deep red precipitate with Million's reagent, it can be concluded that

AK is a carbohydrate and L is a protein
BK is alkaline and L is acidic
CK is unsaturated and L is a reducing sugar
DK is a reducing agent and L is an amino acid
View Explanation & Discuss
Question 584
waec 2000

Which of the following needs to be hydrolyzed before it shows reducing property?

AGlucose
BMaltose
CSucrose
DFructose
View Explanation & Discuss
Question 585
waec 2000

Which of the following is correct about both compounds shown below? CH3CH 2CH2OH;CH 3
CH 2CH(OH)CH3

AThey have identical physical properties
BThey are structural isomers
CTheir general molecular formula is the same
DThey are oxidized to alkanones
View Explanation & Discuss
Question 586
waec 2000

C8H18 will undergo the following reactions except

Acracking
Bcombustion
Csubstitution
Daddition
View Explanation & Discuss
Question 587
waec 2000

2 moles of hydrogen gas will react completely with one mole of....

ACH2=CHCl
BCH3-CH=CH2
CC6H5-CH3
DCH≡C-CH2-CH3
View Explanation & Discuss
Question 588
waec 2000

Which of the following procedures is suitable for identifying the food colouring added to a pastry sample?

Acarry out some food tests
Bexamine the pastry sample under a microscope
CDo a chromatogram of the colouring extract
D.determine the molar mass of the colouring
View Explanation & Discuss
Question 589
waec 2000

Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes?

AThe cathode becomes coated with copper
BBoth electrodes gain electrons
CThe blue colour of the solution fades gradually
DThe anode increases in mass
View Explanation & Discuss
Question 590
waec 2000

0.10 mol dm-3 NaCI conducts electricity better than 0.10 mol dm-3 CH3COOH because the solution of NaCI

Acontains more ions
Bis neutral to litmus
Chas a lower molar mass
Dhas a higher pH
View Explanation & Discuss
Question 591
waec 2000

An iron nail placed in a solution copper (ll) tetraoxosulphate (VI) is soon covered with a deposit of copper. Which of the following equations represents the reactions ?

AFe 2+ (aq) + Cu(s) → Fe 3+ + Cu 2+ (aq)
BFe 2+ (aq) + Cu(s) → Fe(s) + Cu2+ (aq)
CFe (s) + Cu2+ (aq) → Fe2+(aq) + Cu2+ (aq)
DFe(s) + Cu2+ → Fe2+(aq) + Cu(s)
View Explanation & Discuss
Question 592
waec 2000

In which of the following is the oxidation number of sulphur equal to -2?

AS8
BH2S
CSO 2
DSO 3 2-
View Explanation & Discuss
Question 593
waec 2000

What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O

A1
B6
C8
D12
View Explanation & Discuss
Question 594
waec 2000

Which of the following will displace copper from a solution of copper (ll) salt?

AAluminium ions
BMagnesium
CSilver
DZinc ions
View Explanation & Discuss
Question 595
waec 2000

A finely divided form of a metal burns more readily in air than the rod form because the rod has

Ahigher molar mass
Bsmaller surface area
Cprotective oxide coating
Ddiferent chemical properties
View Explanation & Discuss
Question 596
waec 2000

What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO2 + O2 ⇌ 2SO3; ∆H = - xKJmol-1

ADecreases the value of ∆H
BIncreases the collision rate of reactant particles
CShifts equilibrium position to the right
DReduces the time for attainment of equilibrium
View Explanation & Discuss
Question 597
waec 2000

Chemical equilibrium is attained when

Areactants in the system are used up
Bconcentrations of the products are greater than those of the reactants
Cconcentrations of the reactants and products remain constant
Dreactants stop forming the products
View Explanation & Discuss
Question 598
waec 2000

What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3?

ARedox reaction
BDestructive distillation
CDehydration
DNutralization
View Explanation & Discuss
Question 599
waec 2000

Which of the following salts is an acid salt?

AMgSO 37H 2O
B(NH 4) 2CO
CKHSO4
DCH3COONa
View Explanation & Discuss
Question 600
waec 2000

Which of the following compounds dissolves in water to give an alkaline solution?

AAmmonium chloride
BSodium chloride
CSulphur (IV) oxide
DPotassium oxide
View Explanation & Discuss
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