Question Library
Browse, filter, and study verified past examination questions with step-by-step mathematical reasoning.
Searching 18,000+ Questions...
Sifting topics, KaTeX formulas & verified solutions
Showing 24826–24840 of 29821 verified questions
Sort by:
Chemistry
WAEC / WASSCE 1991
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
When starch undergoes complete enzyme-catalyzed hydrolysis, the resulting product is
A
glucose
B
maltose
C
sucrose
D
fructose
E
cellulose
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 #36142)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the reactions represented by the following equations will take place at room temperature?
A
C 6 H2O → CO + H2
B
CuO + H2 → Cu + H2O
C
N2 + 3H2 → 2NH3
D
2Na + 2H2O → 2NaOH + H2
E
2Fe + 3CI2 → 2FeCI3
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 #36143)
Chemistry
WAEC / WASSCE 1991
Organic Chemistry I: Hydrocarbons & Crude Oil
Which of the following is not a direct petroleum product?
A
Methane
B
Ethanol
C
Petrol
D
Vaseline
E
Kerosene
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 #36144)
Chemistry
WAEC / WASSCE 1991
Atomic Structure, Orbitals & Nuclear Chemistry
How many principal electronic shells has an atom whose electronic configuration is shown below? 1s22s22p63s1
A
1
B
2
C
3
D
4
E
11
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 #36145)
Chemistry
WAEC / WASSCE 1991
Chemical Bonding & Intermolecular Forces
Which of the following properties is not characteristic of electrovalent compounds?
A
formation of crystalline solids
B
solubility in polar solvents
C
high vapour pressures
D
high melting and boiling points
E
ability to conduct electricity in aqueous solution
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 #36146)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
Compounds that have the same molecular formula but different structures are said to be
A
allotropic
B
polymorphic
C
polymeric
D
isomeric
E
isotopic
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 #36147)
Chemistry
WAEC / WASSCE 1991
Non-Metals & Their Compounds
In which of the following crystals are the particles held by van der Waal's forces only?
A
Sodium chloride
B
Ice
C
Diamond
D
Iodine
E
Quartz
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 #36148)
Chemistry
WAEC / WASSCE 1991
Electrolysis & Electrochemical Cells
A current of 4.0 amperes was passed through copper (ll) tetraoxosulphate (IV) solution for one hour using copper electrodes. What was the mass of copper deposited? (Cu = 64, 1F = 96500 C)
A
3.2g
B
4.8g
C
6.4g
D
48g
E
96g
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 #36149)
Chemistry
WAEC / WASSCE 1991
Water, Solutions & Solubility
When a crystal was added to its solution, it did not dissolve and the solution remained unchanged, showing that the solution was
A
concentrated
B
supersaturated
C
unsaturated
D
colloidal
E
saturated
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #36150)
Chemistry
WAEC / WASSCE 1991
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
An organic compound which reacts readily with bromine to form a compound with the formula CH3CHBrCH2Br is
A
ethene
B
propane
C
butane
D
propene
E
propyne
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
X + \(Br_2\) → \(CH_3CHBrCH_2Br\)
The compound must be propene because it is unsaturated and does react with bromine water to form 1,2, - dibromo- propane, unlike propyne, which will give a different product.
Source: Myschool Past Questions Archive (Record #36151)
Chemistry
WAEC / WASSCE 1991
Acids, Bases, pH & Salts
river contaminated by alkali waste will have a pH of about.
A
1
B
3
C
5
D
7
E
9
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #36152)
Chemistry
WAEC / WASSCE 1991
Acids, Bases, pH & Salts
In solution, aminoethanoic acid (glycine) can be represented as NH+3 CH2COO. This implies that it
A
is soluble in all inorganic liquids
B
can function as a weak acid or a weak base
C
does not form salt with mineral acids
D
is highly acidic
E
cannot form esters with alkanols
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 #36153)
Chemistry
WAEC / WASSCE 1991
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Hydrogen is used for the following except
A
manufacturing of ammonia
B
synthesis of hydrochloric acid
C
extinguishing fire
D
conversion of coal to petrol
E
manufacture of margarine
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 #36154)
Chemistry
WAEC / WASSCE 1991
Atomic Structure, Orbitals & Nuclear Chemistry
Which of the following is suitable for determining different isotopes present in an element which exhibits isotopy?
A
Sensitive weighing balance
B
Cathoda ray tube
C
Mass spectrometer
D
Geiger muller counter
E
Eudiometer
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 #36155)
Chemistry
WAEC / WASSCE 1991
Nature of Matter & Separation Techniques
Solution
C is a mixture of an organic and an inorganic salt. The test recorded in the table below were performed as indicated,
(a)Copy and complete the table as appropriate.
Test
Observation
Inference
(i) C + water mixed thoroughly and filtered
Partially soluble, colourless filtrate, white residue
(ii) Portion of filtrate from (i) + NH\(_{3(aq)}\) in drops, then in excess
White precipitate which dissolves in excess to give a colourless solution
(iii) Portion of filtrate from (i) + NH\(_3\) in drops, then in excess
White precipitate insoluble in excess
(iv) Portion of filtrate from (i) + conc. HCl + heat
White precipitate which dissolves on warming and reappears on cooling
(v) Portion of filtrate from (i) + conc. H\(_2\)SO\(_4\) + gentle warming
Brown fumes produced on warming
(vi) Residue from (i) + iodine solution
Blue-black colouration
(vii) Residue from (i) + Fehling's solution + heat
(vii) Residue from (i) + dil HCl solution + heat + Fehling's solution
(b) From the information provided and your inference, identify the compounds of C
(c) Describe the action of heat on a solid sample of the inorganic component Write an equation for the reaction.
(d) State what would be observed if an aqueous suspension of the organic component were heated to boiling
A
1
B
3
C
5
D
7
E
9
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
Test
Observation
Inference
(i) C + water mixed thoroughly and filtered
Partially soluble, colourless filtrate, white residue
One soluble and the other is not
(ii) Portion of filtrate from (i) + NH\(_{3(aq)}\) in drops, then in excess
White precipitate which dissolves in excess to give a colourless solution
Zn\(^{2+}\), pb\(^{2+}\) or Al\(^{3+}\) present
(iii) Portion of filtrate from (i) _ NH\(_3\) in drops, then in excess
White precipitate insoluble in excess
Pb\(^{2+}\) or Al\(^{3+}\) present
(iv) Portion of filtrate from (i) + conc. HCl + heat
White precipitate which dissolves on warming and reappears on cooling
Pb\(^{2+}\) confirmed
(v) Portion of filtrate from (i) + conc. H\(_2\)SO\(_4\) + gentle warming
Brown fumes produced on warming
fumes of NO\(_2\); NO\(_3\) + present
(vi) Residue from (i) + iodine solution
Blue-black colouration
Residue is starch
(vii) Residue from (i) + Fehling's solution + heat
No precipitate or any visible reaction
Starch is non-reducing or reducing sugar absent
(vii) Residue from (i) + dil HCl solution + heat + Fehling's solution
Brick - red precipitate
Starch has been hydrolysed to reducing sugar
(b) C is a mixture and lead II trioxonitrate (V) is one
(c) The precipitate (makes a cracking sound) produced copious brown fumes of Nitrogen (IV) oxide on heating. The residue turns red when hot and yellow when cold, lead (II) oxide and a gas that relights a glowing splint evolved. Pb(NO\(_3\))\(_2\) \(\to\) PbO + 2NO\(_2\) + O\(_2\)
(d) It will give a colloidal solution (or jelly-like solution)
Source: Official Exam / Past Question Archive