WAEC Chemistry questions

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

All topics Acids, bases and salts · 26 Air · 16 Atomic structure and bonding · 26 Chemical combination · 27 Chemical equilibrium · 16 Chemistry and industry · 17 Electrolysis · 19 Energy changes · 16 Environmental pollution · 15 Kinetic theory of matter and gas laws · 18 Metals and their compounds · 23 Non-metals and their compounds · 22 Organic compounds · 29 Oxidation and reduction · 19 Rates of chemical reaction · 16 Separation of mixtures and purification · 18 Solubility · 16 Water · 18

Question 261· Organic compounds· WAEC
The general formula of the alkanes is
Show answer
Answer: B. CₙH₂ₙ₊₂
Explanation and discussion
Question 262· Organic compounds· WAEC
The next member of the alkane series after propane is
Show answer
Answer: C. butane
Explanation and discussion
Question 263· Organic compounds· WAEC
Saponification is the
Show answer
Answer: C. alkaline hydrolysis of fats to make soap
Explanation and discussion
Question 264· Organic compounds· WAEC
How many structural isomers has butane, C₄H₁₀?
Show answer
Answer: D. 2
Explanation and discussion
Question 265· Organic compounds· WAEC
Which of the following is produced by the fermentation of glucose?
Show answer
Answer: D. Ethanol
Explanation and discussion
Question 266· Organic compounds· WAEC
Isomers have the same
Show answer
Answer: D. molecular formula but different structures
Explanation and discussion
Question 267· Organic compounds· WAEC
Alkenes decolourise bromine water because they
Show answer
Answer: A. undergo addition reactions
Explanation and discussion
Question 268· Organic compounds· WAEC
Cracking of long-chain hydrocarbons produces
Show answer
Answer: B. shorter alkanes and alkenes
Explanation and discussion
Question 269· Organic compounds· WAEC
The IUPAC name of CH₃CH₂OH is
Show answer
Answer: A. ethanol
Explanation and discussion
Question 270· Organic compounds· WAEC
The usual laboratory test for unsaturation in an organic compound uses
Show answer
Answer: A. bromine water
Explanation and discussion
Question 271· Oxidation and reduction· WAEC
In the reaction Fe₂O₃ + 3CO → 2Fe + 3CO₂, the substance that is reduced is
Show answer
Answer: B. Fe₂O₃
Explanation and discussion
Question 272· Oxidation and reduction· WAEC
Find the oxidation number of nitrogen in NO₂.
Show answer
Answer: C. +4
Explanation and discussion
Question 273· Oxidation and reduction· WAEC
In terms of electrons, oxidation is
Show answer
Answer: D. loss of electrons
Explanation and discussion
Question 274· Oxidation and reduction· WAEC
Which of these is an oxidising agent?
Show answer
Answer: D. acidified potassium heptaoxodichromate(VI)
Explanation and discussion
Question 275· Oxidation and reduction· WAEC
Acidified potassium dichromate(VI) turns from orange to green when it
Show answer
Answer: C. is reduced
Explanation and discussion
Question 276· Oxidation and reduction· WAEC
In the reaction CuO + H₂ → Cu + H₂O, copper(II) oxide is
Show answer
Answer: C. reduced
Explanation and discussion
Question 277· Oxidation and reduction· WAEC
The oxidation number of chromium in K₂Cr₂O₇ is
Show answer
Answer: C. +6
Explanation and discussion
Question 278· Oxidation and reduction· WAEC
The oxidation number of sulphur in H₂SO₄ is
Show answer
Answer: A. +6
Explanation and discussion
Question 279· Oxidation and reduction· WAEC
Which of these is a redox reaction?
Show answer
Answer: D. Zn + CuSO₄ → ZnSO₄ + Cu
Explanation and discussion
Question 280· Oxidation and reduction· WAEC
What is the oxidation number of chromium in potassium heptaoxodichromate(VI), K₂Cr₂O₇?
Show answer
Answer: C. +6
Explanation and discussion

Practise Chemistry like the real exam. A timed CBT, your score, and the topics to fix.

Start a Chemistry test

WAEC Chemistry questions

The general formula of the alkanes is

The next member of the alkane series after propane is

Saponification is the

How many structural isomers has butane, C₄H₁₀?

Which of the following is produced by the fermentation of glucose?

Isomers have the same

Alkenes decolourise bromine water because they

Cracking of long-chain hydrocarbons produces

The IUPAC name of CH₃CH₂OH is

The usual laboratory test for unsaturation in an organic compound uses

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

Find the oxidation number of nitrogen in NO₂.

In terms of electrons, oxidation is

Which of these is an oxidising agent?

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

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

Which of these is a redox reaction?

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