1997 - WAEC Chemistry Past Questions and Answers - page 2
11
An acid is a substance which in the presence of water produces
A
salts
B
oxygen
C
effervescence
D
hydroxonium ions
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12
Which of the following is a general method of preparing acids?
A
Direct combination of constituent elements
B
Double decomposition involving a salt solution
C
Reaction between an anhydride and water
D
Reaction between a base and an amphoteric oxide
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13
Which of the following is a general method of preparing acids?
A
Direct combination of constituent elements
B
Reaction between a base and an amphoteric oxide
C
Double decomposition involving a salt solution
D
Reaction between an anhydride and water
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14
The loss of molecules of water of crystallization to the atmosphere by some crystalline salts is known as
A
efflorescence
B
effervescence
C
phosphorescence
D
fluorescence
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15
Which of the following ions will migrate to the cathode during electrolysis?
A
Zinc ions
B
Chloride ions
C
Sulphide ions
D
Tetraoxosulphate (Vl) ions
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16
What quantity of electrons (in mole) is lost when one mole of iron (ll) ions is oxidized to iron (lll) ions?
A
5 mole
B
4 mole
C
3 mole
D
2 mole
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17
The common feature of reactions at the anode is that
A
electrons are consumed
B
oxidation is involved
C
ions are reduced
D
the electrode dissolves
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18
From the following equations, what is the order of decreasing reactivity of X, Y and Z? Y (s) + X2+(aq) → Y2+
A
X>Y>Z
B
Y > X > Z
C
Z > Y > X
D
Y > Z > X
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19
What is the value of x in the following equation? MnO- 4 + 4H+ + xe- → MnO 2 + 2H2O
A
2
B
3
C
4
D
7
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20
If the value of ∆H for a reaction is negative, it means that the reaction is
A
slow
B
exothermic
C
spontaneous
D
irreversible
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