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Chemistry
WAEC / WASSCE 2008
Acids, Bases, pH & Salts
Solution
When concentrated \(H_2SO_4\) is added to NaCI (s), the gas evolved
A
bleaches damp blue litmus paper
B
forms a white preciptate with AgNO3(aq)
C
forms a white precipitate with BaCI2(aq)
D
turns moist red litmus paper blue
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
2\(NaCl_{(aq)} + H_2SO_{4(aq)} → Na_2SO_{4(aq)} + 2HCl_{(g)}\)
This gas(hydrochloride gas) turns damp/moist blue litmus paper red while reacting with \(AgNO_{3(aq)}\), a white precipitate of AgCl is produced which is soluble in ammonia solution but insoluble in \(HNO_3\)
Source: Myschool Past Questions Archive (Record #37282)
Chemistry
WAEC / WASSCE 2008
Reaction Rates & Chemical Equilibrium
The collision theory proposes that
A
reactants collide more frequently to bring about reduction in the reaction rate
B
all collisions of reactants are effective
C
reactants must collide with a certain minimum amount of energy to from products
D
the fewer the collisions the faster the reaction rate
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #37283)
Chemistry
WAEC / WASSCE 2008
Chemical Energetics & Thermochemistry
Which of the following set of equations could be used to represent the standard enthalpy of formation of glucose?
A
6C (s) + 6H 2(g) + 3O2(g) → C 6H12O6(s)
B
6CO2(g) + 6H2O (l) → C6H12O6(s) + 6O 2(g)
C
6C(g) + 6H 2(g) + 3O2(g) → C6H12O 6(s)
D
6C(g) + 6H 2(g) + 3O2(g) → C 6H 12O 6(aq)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #37285)
Chemistry
WAEC / WASSCE 2008
Acids, Bases, pH & Salts
The colour of phenolphthalein indicator in dilute HNO is
A
colourless
B
orange
C
pink
D
purple
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #37286)
Chemistry
WAEC / WASSCE 2008
Acids, Bases, pH & Salts
An aqueous solution of CaCI2 is
A
acidic solution
B
alkaline solution
C
a buffer solution
D
a neutral solution
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #37287)
Chemistry
WAEC / WASSCE 2008
Acids, Bases, pH & Salts
Solution
Which of the following compounds would dissolved in water to give a solution whose pH is less than 7?
A
AI(NO3)3
B
KNO3
C
N2O
D
NH3
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Aluminum nitrate (Al(NO3)3) is a salt that dissolves in water to produce hydrogen ions (H\(^+\)), which are acidic:
Al(NO\(_3\))\(_3\) → Al\(^{3+}\) + 3NO\(_3\)\(^-\)
Al\(^{3+}\) + 3H\(^2\)O → Al(OH)\(_3\) + 3H\(^+\)
The released hydrogen ions (H\(^+\)) increase the acidity of the solution, resulting in a pH less than 7.
The other options:
B. Potassium nitrate (KNO\(_3\)) is a neutral salt and does not affect the pH.
C. Nitrous oxide (N\(^2\)O) is a gas and does not dissolve in water to affect pH.
D. Ammonia (NH\(_3\)) is a base and would increase the pH of the solution (make it more alkaline).
So, aluminum nitrate (Al(NO3)3) is the correct answer.
Source: Myschool Past Questions Archive (Record #37288)
Chemistry
WAEC / WASSCE 2008
Stoichiometry, Mole Concept & Volumetric Analysis
Consider the reaction represented by the question below: KOH(aq) + HCI(aq) → KCI(aq) + H2O(l) What volume of 0.25 mol dm-3 KOH would be required to completely neutralize 40 cm3 of 0.10 mol dm -3 HCI?
A
40 cm3
B
32cm3
C
24cm3
D
16cm3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #37289)
Chemistry
WAEC / WASSCE 2008
Water, Solutions & Solubility
When 100 cm3 of a saturated solution of KCIO3 at 40oC is evaporated, 14 g of the salt is recovered what is the solubility of KCIO3 at 40oC? [KCIO3 = 122.5]
A
11.42 mol dm-3
B
8.80 mol dm-3
C
1. 14 mol dm-3
D
0.88 mol dm-3
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #37290)
Chemistry
WAEC / WASSCE 2008
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The high solubility of ethanol in water is due to its
A
low boiling point
B
low freezing point
C
covalent nature
D
hydrogen bonding
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #37291)
Chemistry
WAEC / WASSCE 2008
Reaction Rates & Chemical Equilibrium
Consider the equilibrium reaction represented by the equation: 2SO2(g) + O2(g) ⇌ 2SO3(g) ∆H = - 197 kJmol-1. At equilibrium, increase in the total pressure of the system brings about
A
decrease in rate of the reaction of the system
B
decrease in temperature of the system
C
increase in temperature of SO3
D
increase in concentration of SO2
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #37292)
Chemistry
WAEC / WASSCE 2008
Electrolysis & Electrochemical Cells
In dry Leclanche cell, manganese (IV) oxide acts as
A
a reducing agent
B
binding agent
C
catalyst
D
depolarizer
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #37293)
Chemistry
WAEC / WASSCE 2008
Electrolysis & Electrochemical Cells
Oxidation takes place at the anode during electrolysis because the anode
A
is deficient in electrons
B
is deficient in protons
C
has excess electrons
D
has attraction for positive ions
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #37294)
Chemistry
WAEC / WASSCE 2008
Electrolysis & Electrochemical Cells
Calculate the quantity of electricity passed when 0.4 A flows for 1 hour 20 minutes through an electrolytic cell
A
4800C
B
3840 C
C
1920 C
D
32 C
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #37295)
Chemistry
WAEC / WASSCE 2008
Nature of Matter & Separation Techniques
A mixture of kerosene and diesel oil can be separated by
A
crystallization
B
distillation
C
precipitation
D
sublimation
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #37296)
Chemistry
WAEC / WASSCE 2008
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
Which of the following compounds would not give a precipitate with ammoniacal AgNO3 solution?
A
CH3 C≡CCH3
B
HC≡CH
C
CH3C≡CH
D
CH3CH2C≡CH
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Only terminal alkyne(simply, the alkyne in which the triple bonded carbon atoms are at the extreme positions.) reacts with ammonical AgNO3 and gives a white precipitate,
therefore, the correct option is A (Non-Terminal Alkyne has a triple bond at any place other than the end positions).
Source: Myschool Past Questions Archive (Record #37297)