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If sulphur is dissolved in carbon (IV) sulphide and the solution is allowed to evaporate, the allotrope of sulphur formed is
Aplastic sulphur
Bamorphous sulphur
Crhombic sulphur
Dmonoclinc sulphur
Ecolloidal sulphur
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Question 782
waec1989
If sulphur is dissolved in carbon (IV) sulphide and the solution allowed to evaporate the allotrope of sulphur formed is
Aplastic sulphur
Bamorphous sulphur
Crhombic sulphur
Dmonoclinc sulphur
Ecolloidal sulphur
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Question 783
waec1989
Given that 1 mole of carbon -12 weighs 12.0g, how many atoms are there in 24.0g magnesium? (C = 12, Mg = 24, NA = 6.02 x 10 23mol-1)
A1/2 x 6.02 x 10 23
B1 x 6.02 x10 23
C2 x 6.02 x 10 23
D3x 6.02 x 10 23
E4x 6.02 x 10 23
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Question 784
waec1989
Which of the following is used extensively in manufacturing photographic chemicals?
AAluminium chloride
BZinc chloride
CSilver chloride
DMercury (ll) chloride
Elron (ll) chloride
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Question 785
waec1989
Given the following half-cell reaction; 2Cl(aq) → CI2(g) + 2e, how many mole of electrons will be required to produce 1.12dm3 of chlorine gas at s.t.p? (Molar volume of a gas at s.t.p. = 22.4dm 3)
A1.00
B0.40
C0.20
D0.10
E0.01
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Question 786
waec1989
Octane number is highest in petrol containing a high proportion of
Aheptane
Boctane
C2-methylpentane
D2, 4-dimethylpentane
E2,2,4-trimethylpentane
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Question 787
waec1989
The rate of the hydrogen in the reaction Zn(s) + 2HCI (aq) → ZnCI 2(g) + H 2(aq) + H 2(g) can be increased by
Ausing Zinc powder instead of Zinc granules
Busing dilute instead of concentrated hydrochloric acid
Ccooling the container in which the mixture is placed
Dusing an alloy of zinc instead of pure zinc
Eusing hydrogen chloride gas instead of hydrochloric acid solution
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Question 788
waec1989
Why is potassium fluoride added to the electrolyte in the extraction of sodium from fused sodium chloride?
APure sodium chloride does not conduct electricity
BPotassium fluoride prevents the sodium produced from attacking the electrodes
CPotassium fluride increases conductivity
DPotassium fluride reduces the temperature at which sodium chloride fuses
Ethe potassium fluride acts as a catalyst
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Question 789
waec1989
Locally produced soap in which wood ash is used as the base is usually soft because the wood ash contains a lot of
Asodium ions
Bpotassium ions
Clithium ions
Dcalcium ions
Emagnesium ions
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Question 790
waec1989
Copper can best be purified by
Aroasting the impure copper in a blast furnace
Bheating the oxide with coke
Celectrolyzing a copper (ll) salt solution using the impure copper as the anode
Dconverting the impure copper to a trioxonitrate (V)
Ewashing the impure copper with sodium hydroxide solution
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Question 791
waec1989
Which of the following carbohydrates does NOT usually occur in the crystalline form?
AFructose
BGlucose
CSucrose
DMaltose
ECellulose
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Question 792
waec1989
When an element can exist in two or more forms in the same physical state, the element is said to exhibit
Aisotopy
Bisomerism
Callotropy
Dhygroscopy
Esublimation
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Question 793
waec1989
Given that for the reaction KOH (aq) + HCI(aq) → KCI(aq) + H2O(L) H = - 54 Kj mol-1. What is the quantity of heat involved in the reaction?2NaOH(aq) + H2SO 4(aq) → Na2SO4(aq) + 2H 2O(l)?
A- 108Kj
B-54 kj
C-27 kj
D+27 kj
E+54 kj
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Question 794
waec1989
Which of the following gases will bleach moist litmus paper?
ACI2
BCO2
CSO2
DHCI2
EN2 O
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Question 795
waec1989
How many carbon atoms are there in a benzene ring?
A4
B5
C6
D7
E8
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Question 796
waec1989
If 200cm 3 of a gas at s.t.p. has a mass of 0.268g, what is its molar mass? (Molar volume of a gas at s.t.p. = 22.4 dm3)
A300g
B200g
C150g
D30g
E15g
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Question 797
waec1989
The following are miscible with water except
Aethylethanoate
Bmethanol
Cethanoic acid
Dmethanoic acid
Eethanol
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Question 798
waec1989
The most suitable method to use when separating an insoluble solid from a liquid is
Aevaporation
Bfiltration
Cmagnetization
Dsublimation
Edistillation
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Question 799
waec1989
Which of the following hydrocarbons is not likely to be present in petrol?
AC14H30
BC10H22
CC9H20
DC7H16
EC5H12
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Question 800
waec1989
The earthly impurities in iron ore are removed in the blast furnace by the reaction
