WAEC - Chemistry (2024)

1
Which of the following gases could be collected by downward displacement of air?
Sagot
(B)
Hydrogen
2
Which of the following substances has the lowest boiling point?
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(C)
Tetrachloromethane
3
The branch of science that deals with the nature and properties of substances and how one substance can be converted to another is known as
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(B)
chemistry
4
The electron configuration 1S\(^2\) 2S\(^2\) 2P\(_x\)\(^2\) contravenes the
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(D)
Hund's rule
5
The oxidation number of Chromium in Na\(_2\)Cr\(_2\)O\(_7\) is
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(B)
+6
6
The most important ore of aluminium is
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(A)
bauxite
7
Bases normally
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(C)
turn litmus paper from red to blue
8
The product formed when concentrated sodium chloride solution is electrolysed using carbon electrodes is
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(C)
sodium hydroxide
9
The product of the reaction between ethanol and excess acidified K\(_2\)Cr\(_2\)O\(_7\) is
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(C)
CH\(_3\)COOH
10
Which of the following statements about ammonium salt is correct? It
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(B)
dissolves in water to form solution of pH < 7
11
Ethanedioic acid is an organic solid that can be purified by
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(C)
crystallization
12
Which of the following functional groups is present in alkanoic acid?
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(A)
-COOH
13
In ethanol, the attractive forces between adjacent molecules are
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(C)
hydrogen bonding and Van der Waal's forces
14
At 25\(^0\)C, the saturated solution of a salt in water was found to contain 0.24g of the salt in 100cm\(^3\). What is the solubility of the salt in gdm\(^{-1}\)?
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(C)
2.40
15
The reaction represented by the equation: Ni\(^{2+}\)\((_{aq}\)) + Fe\((_s\)) → Ni\((_s\)) + Fe\(^{2+}\)\((_{aq}\)) is a redox reaction because
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(D)
Ni\(^{2+}\) ions are reduced and Fe acts as a reducing agent.
16
Which of the following statements describes transition elements? They
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(C)
possess variable oxidation state
17
Aluminium is suitable for making alloys for aircraft construction because it
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(B)
is light and very resistant to corrosion
18
Which of the following arrangements of elements is in order of increasing ionization energy?
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(C)
Al, Si, P, S
19
Consider the reaction represented by the equation:

C\(_3\)H\(_8\) + 5 O\(_2\) → 3CO\(_2\) + 4H\(_2\)O

If 0.1 mole of C\(_3\)H\(_8\) was completely burnt, what volume of CO\(_2\) would be produced at stp? [volume of gas at stp = 22.4dm\(^3\)mol\(^{-1}\)].
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(A)
6.72dm\(^3\)
20
Naturally occurring Boron is made up of 19.9% \(^{10}\)B and 80.1% \(^{11}\)B. The relative atomic mass of Boron is
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(B)
10.8
21
The number of shared pair of electrons in a molecule of methane is
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(B)
4
22
Isotopes of the same element have similar chemical properties because they have the same number of
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(B)
protons
23
Which of the following household liquids would be effective in treating someone with too much acid in the stomach?
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(C)
Milk of Magnesia with pH 10.5
24
The percentage by mass of Oxygen in MgSO\(_4\).7H\(_2\)O is [ M\(_r\) of MgSO\(_4\).7H\(_2\)O = 246 ]
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(C)
71.5%
25
Catalysts alter reaction rates by
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(A)
providing an alternative reaction pathway
26
Ethane of volume 400 cm\(^3\) was completely burnt in excess oxygen according to the following equation:

2C\(_2\)H\(_6\)\(_(g)\) + 7O\(_2\)\(_(g)\) → 6H\(_2\)O\(_(g)\) + 4CO\(_2\)\(_(g)\)

Calculate the volume of steam that would be produced.
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(D)
1200 cm\(^3\)
27
A saturated solution at 30\(^0\)C will normally produce crystals at a temperature of
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(D)
20\(^0\)C
28
The following organic compounds are polymers except
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(D)
fats
29
According to the collision theory of reaction rates, which of the following conditions is not required for two molecules to react? The molecules must
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(A)
come into contact without loss of energy on colliding with each other
30
A weak acid is one which
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(D)
slightly ionizes in water
31
Which of the following conditions are necessary for the preparation of alkanoates from alkanols and alkanoic acid?
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(B)
Conc. H\(_2\)SO\(_4\) and heat
32
The volume of 22g of CO\(_2\) at stp is equivalent to [C =12, O =16, molar volume at stp = 22.4 dm\(^3\) ]
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(C)
11.2 dm\(^3\)
33
Pairs of outermost shell electrons which are not used in bonding are
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(A)
lone pairs
34
\(_8\)X\(^{2-}\) and \(_{10}\)Y are
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(D)
isoelectronic
35
Pure water contaminated with quicklime will have a pH of
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(D)
8
36
The electron configuration of \(_{29}\) Cu is
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(A)
1S\(^2\) 2S\(^2\) 2P\(^6\) 3S\(^2\) 3P\(^6\) 4S\(^1\) 3d\(^{10}\)
37
When s and p block elements react, the bond formed is
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(A)
electrovalent
38
The hardest form of carbon is
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(C)
diamond
39
The metallic bonding in aluminium is strong because of large number of
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(A)
delocalized electrons
40
How many covalent bonds are formed by Nitrogen?
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(C)
3
41
When an element exists in two or more forms in the same physical state, it exhibits
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(B)
allotropy
42
An atom of an element in the ground state contains 8 valence electrons. The element is considered as a
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(C)
noble gas
43
The main function of limestone in the blast furnace during the extraction of iron is to
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(B)
remove impurities
44
Which of the following is a monomer of polythene?
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(C)
Ethene
45
Which of the following compounds is formed by the oxidation of ethanol?
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(D)
CH\(_3\)CO\(_2\)H