WAEC - Chemistry (2024)

1
Which of the following gases could be collected by downward displacement of air?
답변
(B)
Hydrogen
2
Which of the following substances has the lowest boiling point?
답변
(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
답변
(B)
chemistry
4
The electron configuration 1S\(^2\) 2S\(^2\) 2P\(_x\)\(^2\) contravenes the
답변
(D)
Hund's rule
5
The oxidation number of Chromium in Na\(_2\)Cr\(_2\)O\(_7\) is
답변
(B)
+6
6
The most important ore of aluminium is
답변
(A)
bauxite
7
Bases normally
답변
(C)
turn litmus paper from red to blue
8
The product formed when concentrated sodium chloride solution is electrolysed using carbon electrodes is
답변
(C)
sodium hydroxide
9
The product of the reaction between ethanol and excess acidified K\(_2\)Cr\(_2\)O\(_7\) is
답변
(C)
CH\(_3\)COOH
10
Which of the following statements about ammonium salt is correct? It
답변
(B)
dissolves in water to form solution of pH < 7
11
Ethanedioic acid is an organic solid that can be purified by
답변
(C)
crystallization
12
Which of the following functional groups is present in alkanoic acid?
답변
(A)
-COOH
13
In ethanol, the attractive forces between adjacent molecules are
답변
(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\(^{-1}\)?
답변
(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
답변
(D)
Ni\(^{2+}\) ions are reduced and Fe acts as a reducing agent.
16
Which of the following statements describes transition elements? They
답변
(C)
possess variable oxidation state
17
Aluminium is suitable for making alloys for aircraft construction because it
답변
(B)
is light and very resistant to corrosion
18
Which of the following arrangements of elements is in order of increasing ionization energy?
답변
(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\(^{-1}\)].
답변
(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
답변
(B)
10.8
21
The number of shared pair of electrons in a molecule of methane is
답변
(B)
4
22
Isotopes of the same element have similar chemical properties because they have the same number of
답변
(B)
protons
23
Which of the following household liquids would be effective in treating someone with too much acid in the stomach?
답변
(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 ]
답변
(C)
71.5%
25
Catalysts alter reaction rates by
답변
(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.
답변
(D)
1200 cm\(^3\)
27
A saturated solution at 30\(^0\)C will normally produce crystals at a temperature of
답변
(D)
20\(^0\)C
28
The following organic compounds are polymers except
답변
(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
답변
(A)
come into contact without loss of energy on colliding with each other
30
A weak acid is one which
답변
(D)
slightly ionizes in water
31
Which of the following conditions are necessary for the preparation of alkanoates from alkanols and alkanoic acid?
답변
(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\(^3\) ]
답변
(C)
11.2 dm\(^3\)
33
Pairs of outermost shell electrons which are not used in bonding are
답변
(A)
lone pairs
34
\(_8\)X\(^{2-}\) and \(_{10}\)Y are
답변
(D)
isoelectronic
35
Pure water contaminated with quicklime will have a pH of
답변
(D)
8
36
The electron configuration of \(_{29}\) Cu is
답변
(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
답변
(A)
electrovalent
38
The hardest form of carbon is
답변
(C)
diamond
39
The metallic bonding in aluminium is strong because of large number of
답변
(A)
delocalized electrons
40
How many covalent bonds are formed by Nitrogen?
답변
(C)
3
41
When an element exists in two or more forms in the same physical state, it exhibits
답변
(B)
allotropy
42
An atom of an element in the ground state contains 8 valence electrons. The element is considered as a
답변
(C)
noble gas
43
The main function of limestone in the blast furnace during the extraction of iron is to
답변
(B)
remove impurities
44
Which of the following is a monomer of polythene?
답변
(C)
Ethene
45
Which of the following compounds is formed by the oxidation of ethanol?
답변
(D)
CH\(_3\)CO\(_2\)H