WAEC 2022 Chemistry | Objective

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Question 1 View Details
The by-product of fermentation of sugar is
Correct A. carbon (IV) oxide
B. ethanoic acid.
C. propanol.
D. propan-1, 2, 3-triol.

Correct Answer: A

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Question 2 View Details
Which of the following sugars is a product of the condensation of monosaccharides?
A. Galactose
Correct B. Maltose
C. Glucose
D. Fructose

Correct Answer: B

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Question 3 View Details
The cleansing effect of soap is low in acidic water because of
Correct A. the formation of unionized fatty acid.
B. increase in the pH of the soap molecules.
C. anti-biodegradable effect of hydrogen ions.
D. the hardness of the acidic water.

Correct Answer: A

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Question 4 View Details
The following compounds are condensation polymers except
A. nylon.
B. protein.
C. starch
Correct D. polyethene.

Correct Answer: D

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Question 5 View Details
What amount of electricity is required to deposit one mole of aluminium from a solution of \( \mathrm{AlCl}_{3} \) ?
Correct A. One Faraday
B. One ampere
C. Three Faradays
D. Three amperes

Correct Answer: A

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Question 6 View Details
Which of the following compounds would react rapidly with bromine?
A. Benzene
B. Hexane
Correct C. Hexene
D. Hexanol

Correct Answer: C

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Question 7 View Details
Alkanols can be manufactured from alkenes by the initial reaction of alkenes with
A. bromine in tetrachloromethane
B. concentrated tetraoxosulphate (VI) acid.
Correct C. aqueous potassium tetraoxomanganate (VII).
D. sodium hydroxide solution.

Correct Answer: C

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Question 8 View Details
Which of the following statements about the standard hydrogen electrode is not correct?
A. The hydrogen gas is at a pressure of 1 atmosphere
B. solution containing \( 1 \mathrm{~mol} d m^{-3} \) of \( \mathrm{H}_{(\text {qu })}^{+} \) ions is used
C. A platinum electrode is used
Correct D. The temperature is kept at \( 20^{\circ} \mathrm{C} \)

Correct Answer: D

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Question 9 View Details
If 60 g of M combines with 24 g of oxygen, what would the empirical formula of the oxide be?
Question 10 View Details
The products of the electrolysis of dilute sodium chloride using carbon electrodes are
A. chlorine and sodium.
B. oxygen and hydrogen.
Correct C. chlorine and hydrogen.
D. hydrogen and oxygen.

Correct Answer: C

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Question 11 View Details
Determine the quantity of electricity used when a current of 0.20 amperes is passed through an electrolytic cell for 60 minutes.
Question 12 View Details
Oxochlorate (1) acid is used as a bleaching agent because it is
A. a weak acid
B. a reducing agent
Correct C. an oxidizing agent
D. a strong acid

Correct Answer: C

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Question 13 View Details
The IUPAC name for \( \mathrm{CH}_{3} \mathrm{CHCH}_{3} \mathrm{CH}- \mathrm{ClCHCH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3} \) is
A. 2, 4 dimethyl-3-chlorohexane
B. 3, 5-dimethyl-4 chlorohexane
Correct C. 4-chloro-3, 5-dimethylhexane
D. 3-chloro-2, 4. dimethylhexane.

Correct Answer: C

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Question 14 View Details
A colourless gas with a pungent smell is evolved when dilute hydrochloric acid is added to a sample of a salt. The gas evolved could turn.
A. acidified KMnO solution colourless.
Correct B. \( ext{Fe} ext{(NO}_{3} ext{)}_{2} \) solution green
C. \( ext{Pb} ext{(NO}_{3} ext{)}_{2} \) paper black.

Correct Answer: B

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Question 15 View Details
If 5.0 g of marble reacts with \( 25.0 \mathrm{~cm}^{3} \) hydrochloric acid, which of the following combinations has the fastest reaction rate?
A. Marble chips and 2.0 \( ext{mol} \text{dm}^{-3} \text{HCl} \)
B. Marble chips and mol dm
Correct C. powdered marble and 2.5 mol dm \( ext{HCl}_{\text{(aq)}} \)
D. powdered marble and 2.0 mol dm \text{HCl}_{\text{aq}}

Correct Answer: C

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Question 16 View Details
Increasing the temperature generally
Correct A. decreases the solubility of a solid in a liquid but increases the solubility of a gas in a liquid.
B. increases the solubility of a solid in a liquid but decreases the solubility of a gas in a liquid
C. increases the solubility of both a solid and a gas in a liquid.
D. decreases the solubility of both a solid and a gas in a liquid.

Correct Answer: A

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Question 17 View Details
A white precipitate was formed when \( \mathrm{BaCl}_{2(aq)} \) was added to an aqueous solution of a salt X. The precipitate dissolved in dilute HCl with rapid effervescence. Salt \( extbf{X} \) is likely to contain.
A. \( \mathrm{SO}_{4}^{2-} \) ions.
B. \( \mathrm{SO}_{3}^{2-} \) ions.
C. \( \mathrm{NO}_{3}^{-} \) ions.
Correct D. \( \mathrm{CO}_{3}^{2-} \) ions.

Correct Answer: D

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Question 18 View Details
Before a reaction could take place, there should be
A. ionization of reactant particles.
B. breakage of bonds of products.
Correct C. breakage of bonds of reactants.
D. ionization of product particles.

Correct Answer: C

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Question 19 View Details
Consider the following reaction equation: \( \mathrm{CaO} + \mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3} \). Calcium oxide is:
A. a reducing agent.
Correct B. an acidic oxide.
C. an oxidizing agent.

Correct Answer: B

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Question 20 View Details
Which of the following acids would form normal salt only?
A. Tetraosulphate (VI) acid
Correct B. trioxonitrate (V) acid
C. tetraoxophosphate (V) acid
D. Trioxosulphate (IV) acid

Correct Answer: B

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Question 21 View Details
What is the partial pressure of oxygen at s.t.p. in a gaseous mixture containing \( 100 \text{cm}^{3} \) of oxygen and \( 900 \text{cm}^{3} \) of nitrogen gas?
A. 1.0 atm
B. 0.1 atm
C. 9.0 atm
Correct D. 0.9 atm

Correct Answer: D

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Question 22 View Details
Graphite is used as a dry lubricant due to the presence of
A. mobile electrons.
B. free electrons.
C. octahedral structures.
Correct D. layered structures.

Correct Answer: D

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Question 23 View Details
Which of the following gases is alkaline?
A. \( \mathrm{NO}_{2} \)
B. \( \mathrm{CO}_{2} \)
Correct C. \( ext{NH}_{3} \)
D. \( ext{N}_{2} ext{O} \)

Correct Answer: C

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Question 24 View Details
Which of the following statements about an equilibrium system is correct?
Correct A. Forward and backward reactions occur at the same rate.
B. The concentrations of reactants must equal that of the products.
C. The concentrations of reactants and products can be changed by adding a catalyst.
D. The concentrations of reactants and products are not affected by a change in temperature.

Correct Answer: A

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Question 25 View Details
Consider the following reaction equation: \( \mathrm{N}_{2(g)} + 3 \mathrm{H}_{2(g)} \rightleftharpoons 2 \mathrm{NH}_{3(g)} ; \Delta \mathrm{H} = -92 \text{ kJ} \). Increasing the temperature of the reaction would
A. shift the equilibrium to the right.
B. increase the yield of ammonia.
C. decrease the amount of hydrogen.
Correct D. decrease the yield of ammonia.

Correct Answer: D

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