WAEC - Chemistry (2022)

1
The by-product of fermentation of sugar is
Answer
(A)
carbon(IV) oxide.
2
Which of the following sugars is a product of the condensation of monosaccharides?
Answer
(B)
maltose
3
The cleansing effect of soap is low in acidic water because of
Answer
(A)
the formation of unionized fatty acid.
4
The following compounds are condensation polymers except
Answer
(D)
polyethene
5
What amount of electricity is required to deposit one mole of aluminium from a solution of AlCl3?
Answer
(C)
Three Faradays
6
Which of the following compounds would react rapidly with bromine?
Answer
(C)
Hexene
7
Alkanols can be manufactured from alkenes by the initial reaction of alkenes with
Answer
(B)
concentrated tetraoxosulphate(VI) acid
8
Which of the following statements about the standard hydrogen electrode is not correct?
Answer
(D)
The temperature is kept at 20 °C
9

If 60 g of M combines with 24 g of oxygen, what would the empirical formula of the oxide be?

( molar mass of M = 120, O = 16)

Answer
(C)
MO\(_{3}\)
10
The products of the electrolysis of dilute sodium chloride using carbon electrodes are

Anode Cathode
Answer
(B)
oxygen and hydrogen.
11
Determine the quantity of electricity used when a current of 0.20 amperes is passed through an electrolytic cell for 60 minutes.
Answer
(D)
720C
12
Oxochlorate(I) acid is used as a bleaching agent because it is
Answer
(C)
an oxidizing agent
13
The IUPAC name for CH\(_{3}\)CHCH\(_{3}\)CHCLCHCH\(_{3}\)CH\(_{2}\)CH\(_{3}\) is
Answer
(D)
3 - chloro - 2, 4 - dimethylhexane
14
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
Answer
(B)
acidified KMnO\(_{4}\) solution colourless
15
If 5.0 g of marble reacts with 25.0 cm3 hydrochloric acid, which of the following combinations has the fastest reaction rate?
Answer
(C)
Powdered marble and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)
16
Increasing the temperature generally
Answer
(B)
increases the solubility of a solid in a liquid but decreases the solubility of a gas in a liquid.
17
A white precipitate was formed when BaCl\(_{2(aq)}\) was added to an aqueous solution
of a salt X. The precipitate dissolved in dilute HCl with rapid effervescence. Salt X is likely to contain
Answer
(B)
SO\(_{3}\) \(^{2-}\) ions
18
Before a reaction could take place, there should be
Answer
(C)
breakage of bonds of reactants
19
Consider the following reaction equation:
CaO + SiO\(_{2}\) ------> CaSiO\(_{3}\)
Silicon(IV) oxide is acting as
Answer
(C)
an acidic oxide
20
Which of the following acids would form normal salt only?
Answer
(B)
Trioxonitrate(V) acid
21
What is the partial pressure of oxygen at s.t.p. in a gaseous mixture containing 100 cm3 of oxygen and 900 cm3 of nitrogen gas?
Answer
(B)
0.1 atm
22
Graphite is used as a dry lubricant due to the presence of
Answer
(D)
layered structures
23
Which of the following gases is alkaline?
Answer
(C)
NH\(_{3}\)
24
Which of the following statements about an equilibrium system is correct?
Answer
(A)
Forward and backward reactions occur at the same rate
25

Consider the following reaction equation
N\(_{2}\)(g) + 3H\(_{2(g)}\) ⇌ 2NH3(g) ∆H = -92kJ

Increasing the temperature of the reaction would

Answer
(D)
decrease the yield of ammonia
26
When air in a syringe is compressed such that there is no change in temperature, the
Answer
(B)
pressure increases
27

Which of the following statements about liquids is/are true?


I. Liquids maintain their volume at constant temperature.
II. Liquids have fixed shape
III. Liquids do not diffuse
IV. Change in pressure affects volume of liquids

Answer
(A)
I only
28
A hydrogen chloride gas reacted with oxygen gas to yield water and chlorine gas. The mole ratio of the hydrogen chloride gas to water is
Answer
(B)
2:1
29
What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm\(^{3}\) cylinder?
[R=0.082 atm dm\(^{-3}\) mol\(^{-1}\) K\(^{-1}\)]
Answer
(C)
3.13
30
If 50 cm\(^{3}\) of a saturated solution of KNO\(_{3}\) at 40 °C contained 5.05 g of the salt, its solubility at the same temperature would be
[KNO\(_{3}\) = 101]
Answer
(A)
1.0 mol dm\(^{-3}\)
31
Which of the following elements would displace copper from a solution of copper ions?
Answer
(C)
lead
32
What is the percentage composition of carbon
in Ca(HCO3)\(_{2}\) ?
[ Ca = 40.0, 0= 16.0, C = 12.0, H= 1.0]
Answer
(B)
14.8%
33
Which of the following bond types is intermolecular?
Answer
(B)
Hydrogen bond
34
The maximum number of covalent bonds formed by nitrogen is
Answer
(D)
4
35
The IUPAC name of the compound CH3CH(CH3)CHCH2 is
Answer
(C)
3 - methyl but - 1 - ene
36
Ionization energy increases across the period in the periodic table because
Answer
(B)
effective nuclear charge increases
37

Which of the following properties indicate that an element is a metal. It


I. reacts with oxygen to form an acidic oxide
II. forms ionic chlorides
III. has variable oxidation states
IV. displaces hydrogen from dilute HCl

Answer
(C)
II and IV only
38
The electron configuration of carbon atom in its excited state is
Answer
(C)
1s\(^{2}\)2s\(^{1}\)2px\(^{1}\)2py\(^{1}\)2pz\(^{1}\)
39

An oxide has the following properties. It


I. is a white powder
II. reacts with HCI.
III. reacts with NaOH
IV. is insoluble in water
The oxide is

Answer
(B)
amphoteric
40
Which of the following statements about atoms of a metal is correct? They
Answer
(D)
are held together by a sea of electron cloud
41
The atom with the electron configuration
1s\(^{2}\)2s\(^{2}\)2p63s\(^{2}\)3p\(^{6}\)3d\(^{10}\)4s\(^{2}\)4p\(^{4}\) is in
Answer
(A)
period 4, p- block
42
Electropositivity of elements across the periodic table normally
Answer
(C)
decreases across the period
43

Consider the following table

Substitute Meltig point / ºC Boiling  point / ºC
P - 78 -25
Q - 8 40
R  - 6 150
S 44 280


Which of the substances is a liquid at room temperature and rapidly evaporates on exposure to air?

Answer
(B)
Q
44
Which of the following oxides is amphoteric?
Answer
(C)
Lead(II) oxide
45
Which of the following processes occur during fractional distillation of petroleum?
Answer
(D)
Evaporation and condensation