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 761· Solubility· JAMB
A saturated solution is one that:
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Answer: D. contains the maximum amount of solute at that temperature
Explanation and discussion
Question 762· Water· JAMB
Which process exchanges the Ca²⁺ and Mg²⁺ ions in hard water for Na⁺ ions?
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Answer: A. passing the water through a permutit (ion-exchange) column
Explanation and discussion
Question 763· Water· JAMB
In water treatment, suspended particles are removed mainly by
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Answer: C. sedimentation and sand filtration
Explanation and discussion
Question 764· Water· WAEC
A deliquescent substance
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Answer: A. absorbs water from the air and dissolves in it
Explanation and discussion
Question 765· Water· JAMB
Temporary hardness of water is removed by
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Answer: D. boiling
Explanation and discussion
Question 766· Water· WAEC
Water from a well tastes better than distilled water because it contains
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Answer: B. dissolved gases and minerals
Explanation and discussion
Question 767· Water· JAMB
Temporary hardness of water is caused by dissolved:
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Answer: B. calcium hydrogentrioxocarbonate(IV)
Explanation and discussion
Question 768· Water· JAMB
Ion-exchange resins soften water by
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Answer: D. replacing calcium and magnesium ions with sodium ions
Explanation and discussion
Question 769· Water· JAMB
Which substance removes both temporary and permanent hardness of water?
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Answer: A. sodium trioxocarbonate(IV) (washing soda)
Explanation and discussion
Question 770· Water· JAMB
Water is regarded as a compound because
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Answer: D. hydrogen and oxygen are always combined in a fixed ratio by mass
Explanation and discussion
Question 771· Water· WAEC
Which substance is added during public water treatment to kill germs?
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Answer: B. chlorine
Explanation and discussion
Question 772· Water· WAEC
Hard water is undesirable for washing because it
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Answer: C. wastes soap by forming scum
Explanation and discussion
Question 773· Water· JAMB
Washing soda crystals, Na₂CO₃·10H₂O, lose water of crystallisation when exposed to air. They are described as
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Answer: B. efflorescent
Explanation and discussion
Question 774· Water· JAMB
Pure water at normal atmospheric pressure boils at
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Answer: D. 100 °C
Explanation and discussion
Question 775· Water· JAMB
Find the percentage of water by mass in Na₂CO₃·10H₂O. [Na = 23, C = 12, O = 16, H = 1]
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Answer: C. 62.9%
Explanation and discussion
Question 776· Water· JAMB
A substance that absorbs moisture from the air and dissolves in it to form a solution is described as
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Answer: D. deliquescent
Explanation and discussion
Question 777· Water· JAMB
Water dissolves many ionic substances because its molecules are
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Answer: C. polar
Explanation and discussion
Question 778· Water· JAMB
Which of the following is hygroscopic and is used as a drying agent?
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Answer: C. concentrated tetraoxosulphate(VI) acid
Explanation and discussion
Question 779· Water· JAMB
In the treatment of town water, alum is added to
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Answer: A. make suspended particles coagulate and settle
Explanation and discussion
Question 780· Water· WAEC
The formula of water shows that it contains hydrogen and oxygen in the ratio, by atoms, of
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Answer: A. 2 : 1
Explanation and discussion

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JAMB and WAEC Chemistry questions

A saturated solution is one that:

Which process exchanges the Ca²⁺ and Mg²⁺ ions in hard water for Na⁺ ions?

In water treatment, suspended particles are removed mainly by

A deliquescent substance

Temporary hardness of water is removed by

Water from a well tastes better than distilled water because it contains

Temporary hardness of water is caused by dissolved:

Ion-exchange resins soften water by

Which substance removes both temporary and permanent hardness of water?

Water is regarded as a compound because

Which substance is added during public water treatment to kill germs?

Hard water is undesirable for washing because it

Washing soda crystals, Na₂CO₃·10H₂O, lose water of crystallisation when exposed to air. They are described as

Pure water at normal atmospheric pressure boils at

Find the percentage of water by mass in Na₂CO₃·10H₂O. [Na = 23, C = 12, O = 16, H = 1]

A substance that absorbs moisture from the air and dissolves in it to form a solution is described as

Water dissolves many ionic substances because its molecules are

Which of the following is hygroscopic and is used as a drying agent?

In the treatment of town water, alum is added to

The formula of water shows that it contains hydrogen and oxygen in the ratio, by atoms, of