WAEC - Chemistry (1998)

1
AN AQUEOUS SOLUTION IS ACIDIC IF
Answer
(E)
it contains more H3O- than OH-
2
The following oxides react with water except
Answer
(E)
CuO
3
Which of the following is not a property of trioxonitrate (V) salts?
Answer
(D)
Production of effervescence with saturated Na2CO3 solution
4
Which of the following methods is suitable for the preparation of an insoluble salt?
Answer
(B)
Double decomposition
5
What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO 2(aq) + 2H2S(g) → 3S (s) + 2H 2O (l)
Answer
(B)
Oxidising agent
6
Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?
Answer
(C)
Dilute sodium chloride solution
7
What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]
Answer
(A)
0.318g
8
How many electrons are removed from Cr2- when it is oxidized to CrO42-?
Answer
(D)
8
9
Substances which absorb water from the atmosphere without dissolving in it are sid to be
Answer
(B)
hygroscopic
10
Pipe-borne water is usually chlorinated in order to
Answer
(D)
kill harmful bacteria in the water
11
Which of the following can be added to dissolve the precipitate formed in the reaction represented by the following equation? CaCl2(aq) + H2C2O 4(s) ⇌ CaC 2O2
Answer
(E)
Aqueous ammonia
12
The spontaneity of a chemical reaction is determined by the change in the
Answer
(C)
free energy of the system
13
Two metallic ions commonly present in hard water are
Answer
(C)
Mg2+ and Ca2+
14
Rusting of iron is an example of
Answer
(D)
redox reaction
15
Aluminium is extracted from
Answer
(C)
bauxite
16
Metals are said to be malleable because they
Answer
(C)
can be beaten into sheets
17
A device used in the laboratory for intermittent production of gases without heating is
Answer
(E)
Kipp's apparatus
18
Which of the following can undergo both addition reactions and substitution reactions?
Answer
(A)
Benzene
19
The liquid product of the destructive distillation of coal is
Answer
(C)
ammoniacal liquor
20
Which of the following alkanes has the highest boiling point?
Answer
(E)
hexane
21
Petrol consists mainly of
Answer
(C)
hydrocarbons
22
Dehydration of ethanol produces
Answer
(C)
ethene
23
When alkanols react with sodium, the ga evolved is
Answer
(A)
hydrogen
24
The products of the reaction between CH3CH 2COOH and CH3OH are H 2
O and
Answer
(A)
CH 3CH2COOCH3
25
A positive reaction to Fehling's test indicates the presence of
Answer
(B)
reducing sugars