1990 - WAEC Chemistry Past Questions & Answers - page 1

1
Catalytic hydrogenation of oils results in the production of
A
soaps
B
detergents
C
alkanes
D
butter
CORRECT OPTION: e
2
Which of the following reaction will not take place under normal conditions?
A
Zn(s) + 2HCI2(aq) + H 2(g)
B
Fe (s) + H 2SO4(aq) → FeSO4(aq) + H2(g)
C
Cu (s) + 2HCI (aq) → CuCI 2(aq) + H2(g)
D
Ca(s) + 2H Ca(OH)2(g)
CORRECT OPTION: c
3
A sample of orange juice is suspected to have been contaminated with a yellow dye. Which of the following methods can be used to detect the dye?
A
Decantation
B
Chromatography
C
Distillation
D
Filtration
CORRECT OPTION: b
4
The electronic configuration 1s2 22s 22p 63s23p 6 is that of a
A
noble gas
B
Group ll element
C
Group lll element
D
Group V element
CORRECT OPTION: a
5
The heat accompanying the reaction represented by the equation H2O (l) → H 2O(g) is described as the heat of
A
solution
B
neutralization
C
vaporization
D
sublimation
CORRECT OPTION: c
6
Aluminum is above iron in the electrochemical series, yet iron corrodes easily on exposure to air while aluminium does not. This is because aluminium
A
has a lower density than iron
B
is a better conductor than iron
C
does not corrode spontaneously
D
forms thin layer of inert oxide in moist air
CORRECT OPTION: d
7
When a solid melts and consequently boils, there is
A
a gradual increase in the average kinetic energy of the particles
B
a sudden decrease in the kinetic energy of the particles
C
no change in the average kinetic energy of the particles
D
a rapid change in the nature of bonding of the com[onents
CORRECT OPTION: a
8
Which of the following compounds will undergo additional reactions?
A
Ethyne
B
Butane
C
Pentane
D
Tetrachloromethane
CORRECT OPTION: a
9
Which of the following reactions does not occur in the blast furnace during the extraction of iron?
A
Fe2O3 (s) + 3CO(g) → 2Fe(l) + 3CO2(g)
B
C2 + CO 2(g)
C
CaO(s) + SiO2(s) → CaSiO 3(s)
D
FeO(s) + CO2(g) + Fe(l)
CORRECT OPTION: e
10
A catayst which increases the rate of a chemical reaction does so by
A
increasing the reaction pathway
B
increasing the surface area of the reactants
C
increasing the pressure on the system
D
decreasing the temperature at which the reaction occurs
CORRECT OPTION: e
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