JAMB and WAEC Chemistry questions

800 questions with answers and explanations. Tap an option to check yourself.

All topics Acids, bases and salts · 58 Air · 37 Atomic structure and bonding · 59 Chemical combination · 58 Chemical equilibrium · 37 Chemistry and industry · 35 Electrolysis · 41 Energy changes · 38 Environmental pollution · 32 Kinetic theory of matter and gas laws · 45 Metals and their compounds · 47 Non-metals and their compounds · 45 Organic compounds · 72 Oxidation and reduction · 41 Rates of chemical reaction · 38 Separation of mixtures and purification · 42 Solubility · 36 Water · 39

Question 601· Organic compounds· JAMB
The fermentation of glucose produces
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Answer: D. ethanol and carbon(IV) oxide
Explanation and discussion
Question 602· Organic compounds· WAEC
The usual laboratory test for unsaturation in an organic compound uses
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Answer: A. bromine water
Explanation and discussion
Question 603· Organic compounds· JAMB
Cracking is the process of
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Answer: B. breaking long-chain hydrocarbons into shorter, more useful ones
Explanation and discussion
Question 604· Organic compounds· JAMB
Ethene decolourises bromine water because it is:
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Answer: B. unsaturated
Explanation and discussion
Question 605· Oxidation and reduction· WAEC
In the reaction Fe₂O₃ + 3CO → 2Fe + 3CO₂, the substance that is reduced is
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Answer: B. Fe₂O₃
Explanation and discussion
Question 606· Oxidation and reduction· JAMB
Which change is a reduction?
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Answer: D. Fe³⁺ → Fe²⁺
Explanation and discussion
Question 607· Oxidation and reduction· WAEC
Find the oxidation number of nitrogen in NO₂.
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Answer: C. +4
Explanation and discussion
Question 608· Oxidation and reduction· JAMB
In terms of electron transfer, oxidation is
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Answer: A. the loss of electrons
Explanation and discussion
Question 609· Oxidation and reduction· JAMB
Find the oxidation number of chromium in K₂Cr₂O₇.
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Answer: B. +6
Explanation and discussion
Question 610· Oxidation and reduction· WAEC
In terms of electrons, oxidation is
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Answer: D. loss of electrons
Explanation and discussion
Question 611· Oxidation and reduction· WAEC
Which of these is an oxidising agent?
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Answer: D. acidified potassium heptaoxodichromate(VI)
Explanation and discussion
Question 612· Oxidation and reduction· WAEC
Acidified potassium dichromate(VI) turns from orange to green when it
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Answer: C. is reduced
Explanation and discussion
Question 613· Oxidation and reduction· JAMB
A metal high in the electrochemical series
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Answer: C. displaces metals below it from solutions of their salts
Explanation and discussion
Question 614· Oxidation and reduction· JAMB
In the reaction 2FeCl₂ + Cl₂ → 2FeCl₃, the oxidising agent is
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Answer: C. Cl₂
Explanation and discussion
Question 615· Oxidation and reduction· WAEC
In the reaction CuO + H₂ → Cu + H₂O, copper(II) oxide is
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Answer: C. reduced
Explanation and discussion
Question 616· Oxidation and reduction· WAEC
The oxidation number of chromium in K₂Cr₂O₇ is
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Answer: C. +6
Explanation and discussion
Question 617· Oxidation and reduction· WAEC
The oxidation number of sulphur in H₂SO₄ is
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Answer: A. +6
Explanation and discussion
Question 618· Oxidation and reduction· JAMB
In the reaction Cl₂ + 2NaOH → NaCl + NaOCl + H₂O, chlorine is
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Answer: C. both oxidised and reduced
Explanation and discussion
Question 619· Oxidation and reduction· WAEC
Which of these is a redox reaction?
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Answer: D. Zn + CuSO₄ → ZnSO₄ + Cu
Explanation and discussion
Question 620· Oxidation and reduction· WAEC
What is the oxidation number of chromium in potassium heptaoxodichromate(VI), K₂Cr₂O₇?
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Answer: C. +6
Explanation and discussion

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JAMB and WAEC Chemistry questions

The fermentation of glucose produces

The usual laboratory test for unsaturation in an organic compound uses

Cracking is the process of

Ethene decolourises bromine water because it is:

In the reaction Fe₂O₃ + 3CO → 2Fe + 3CO₂, the substance that is reduced is

Which change is a reduction?

Find the oxidation number of nitrogen in NO₂.

In terms of electron transfer, oxidation is

Find the oxidation number of chromium in K₂Cr₂O₇.

In terms of electrons, oxidation is

Which of these is an oxidising agent?

Acidified potassium dichromate(VI) turns from orange to green when it

A metal high in the electrochemical series

In the reaction 2FeCl₂ + Cl₂ → 2FeCl₃, the oxidising agent is

In the reaction CuO + H₂ → Cu + H₂O, copper(II) oxide is

The oxidation number of chromium in K₂Cr₂O₇ is

The oxidation number of sulphur in H₂SO₄ is

In the reaction Cl₂ + 2NaOH → NaCl + NaOCl + H₂O, chlorine is

Which of these is a redox reaction?

What is the oxidation number of chromium in potassium heptaoxodichromate(VI), K₂Cr₂O₇?