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 22921–22935 of 29821 verified questions
Sort by:
Chemistry
WAEC / WASSCE 1994
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Glucose can be obtained from starch by
A
hydrogenation
B
dissoiation
C
hydrolysis
D
dialysis
E
dehydration
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 #36348)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
How many faradays of electricity are required to liberate 9g aluminium? (AI = 27)
A
0.1
B
0.3
C
1.0
D
2.7
E
3.0
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 #36349)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
The gaseous product formed when ammonia is passed over heated copper (ll) oxide is
A
oxygen
B
nitrogen
C
hydrogen
D
nitrogen (l) oxide
E
nitrogen (ll) oxide
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 #36372)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is not a halogen?
A
Silicon
B
Fluorine
C
Astatine
D
Bromine
E
lodine
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 #36373)
Chemistry
WAEC / WASSCE 1994
Water, Solutions & Solubility
Solution
Which of the following is likely to have the highest degree of hardness?
A
Carbonated water
B
Distilled water
C
Acidified water
D
Rain water
E
Lime water
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
Hardness in water is mainly due to the presence of dissolved minerals such as calcium and magnesium ions, carbonated water, and rainwater with added carbon dioxide either naturally or artificially do not contain a great amount of these dissolved minerals hence they are less likely to have a high degree of hardness compared to lime water which contains calcium ions from the dissolved calcium hydroxide.
Source: Myschool Past Questions Archive (Record #36374)
Chemistry
WAEC / WASSCE 1994
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
Study the reaction represented by the equation: Alkanol + Alkanoic acid + conc. H\(_2\)SO\(_4\) → Alkanoate + water. The type of process involved in the reverse reaction is
A
Neutralization
B
dehydration
C
hydrolysis
D
decomposition
E
hydrogenation
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The forward reaction is esterification while the reverse reaction is hydrolysis which involves the reaction between Alkanoate and water to produce alkanoic acid and alkanol.
Source: Myschool Past Questions Archive (Record #36375)
Chemistry
WAEC / WASSCE 1994
Non-Metals & Their Compounds
Destructive distillation of coal means
A
heating coal in plentiful supply of air
B
burning coal in air to produce water and carbon (IV) oxide
C
heating coal in the absence of air
D
heating coal in limited supply of air
E
separating coal into various allotropes of carbon
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 #36376)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
When magnesium ribbon burns in air, the products are
A
magnesium nitride and magnesium oxide
B
magnesium nitride and carbon (ll) oxide
C
magnesium oxide and steam
D
magnesium nitride and soot
E
magnesium oxide and carbon (ll) oxide
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 #36377)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
The following compounds contain the same type of bonds except
A
sodium chloride
B
hydrogen chloride
C
magnesium chloride
D
potassium chloride
E
lithium chloride
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 #36378)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
What is the molar mass of an alkyne with the formula Cx H 14? (H = 1, C = 12)
A
86g
B
92g
C
98g
D
110g
E
112g
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 #36379)
Chemistry
WAEC / WASSCE 1994
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
A is a solution containing 0.050 mol. dm of tetraoxosulphate (VI) acid. B is a solution of anhydrous trioxocarbonate (IV).
(a) Put A into the burette and titrate with 20cm\(^3\) or 25cm\(^3\) portions of B using methyl orange as an indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average volume of A used
(b) From your results and the information provided, calculate the:
(i) Concentration of solution B in mol. dm\(^{-3}\)
(ii) mass of sodium tetraoxosulphate (VI) that would be formed in solution of 1dm\(^3\) of solution B were neutralized by solution A
(iii) volume of carbon (IV) oxide at s.t.p. that would be liberated in (b)(ii) above. The equation for the reaction is: N\(_2\)CO\(_{3(aq)}\) + H\(_2\)SO\(_{4(aq)}\) \(\to\) Na\(_2\)SO\(_{4(aq)}\) + H\(_2\)O\(_{(l)}\) + CO\(_{2(g)}\) [O = 16; Na = 23, S = 32; molar volume of gases of s.t.p. = 22.4dm\(^3\)
A
86g
B
92g
C
98g
D
110g
E
112g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Volume of pipette = 25 cm\(^3\)
Indicator - methyl orange
Burette readings
Rough
1st
2nd
3rd
Final burette readings (cm\(^3\))
23.10
45.00
23.60
22.40
Initial burette readings (cm\(^3\))
0.50
22.60
1.20
0.00
burette reading (cm\(^3\))
22.60
22.40
22.40
22.40
(i) Average volume of A used = \(\frac{22.40 + 22.40 + 22.40}{3}\) = 22.40cm\(^3\)
(b)(i) Equation for the reaction, mole ratio of acid to base (salt) is 1 : 1
\(\frac{\text{Molar concentration of A(C\(_A\)) x volume of A(V\(_A\))}}{\text{Molar concentration of B(C\(_B\)) x volume of B(V\(_B\))}}\) = mole reaction of \(\frac{A}{B}\) = \(\frac{0.05 \times 22.40}{C_B \times 25} = \frac{1}{1}\)
C\(_B\) = \(\frac{0.05 \times 22.40 \times 1}{25}\) = 0.0448 mol. dm\(^3\)
(ii) Molar mass of Na\(_2\)SO\(_4\) = (23 x 2) + 32 + (16 x 4) = 142g
Amount of Na\(_2\)CO\(_3\) in 1 dm\(^3\) of B = 0.0448 mole
from equation
1 mole of Na\(_2\)CO\(_3\) = 0.0488 x 142 = 6.36g
(iii) From the equation, 1 mole of Na\(_2\)CO\(_3\) produces 1 mole of CO\(_2\) at s.t.p.
i.e. mole of Na\(_2\)CO\(_3\) produces 22.4 dm\(^3\) of CO\(_2\) at s.t.p
Mole of Na\(_2CO_3\) produces \(\frac{22.4}{1}\) x 0.0448 = 1.00 dm\(^3\)
Source: Official Exam / Past Question Archive
Chemistry
UTME / JAMB 1994
Oxidation, Reduction & Redox Reactions
Solution
MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from
A
+7 to +2
B
+6 to +2
C
+5 to +2
D
+4 to +2
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
\(MnO_{{4}{(aq)}}\) has a charge of \(-1\)
Let the oxidation number of \(Mn\) in \(MnO_{{4}{(aq)}}\) be X
Recall, the oxidation number of \(O_{2}\) is \(-2\)
\(\therefore\) \(X + (-2\times 4) = -1\)
\(X - 8 = -1\)
\(X = +7\)
Source: Myschool Past Questions Archive (Record #44422)
Chemistry
UTME / JAMB 1994
Acids, Bases, pH & Salts
Solution
which of these metals CANNOT replace hydrogen from alkaline solutions?
A
Aluminium
B
Zinc
C
Tin
D
Iron
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Aluminum, Zinc, and Tin react with both acids and alkalis to liberate hydrogen and so all are amphoteric metals except iron.
Iron can displace hydrogen from acids, but not from alkaline solutions. Iron is a metal that is more reactive than hydrogen and therefore can displace hydrogen from acids, but not from alkaline solutions.
In general, metals that are more reactive than hydrogen can displace hydrogen from acids. This means that when a metal reacts with an acid, the metal replaces the hydrogen in the acid, forming a salt and releasing hydrogen gas. Iron is considered a reactive metal and is placed above hydrogen in the reactivity series, which means it can displace hydrogen from acids. In alkaline solutions (solutions with a high pH, like those containing hydroxide ions), the hydrogen is not in a form that can be easily displaced by metals. Instead, the alkaline solution contains hydroxide ions (OH-) and the metal will react with these ions to form a hydroxide or oxide.
Source: Myschool Past Questions Archive (Record #44423)
Chemistry
UTME / JAMB 1994
Stoichiometry, Mole Concept & Volumetric Analysis
Clothes should be properly rinsed with water after bleaching because
A
the bleach decolourizes the clothes
B
chlorine reacts with fabrics during bleaching
C
the clothes are sterilized during bleaching
D
hydrogen chloride solution is produced during bleaching
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 #44425)
Chemistry
UTME / JAMB 1994
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
When sodium ethanoate is treated with a few drops of concentrated tetraoxosulphate(vi)acid. one of the products is
A
CH3COOH
B
CH3COOCH3
C
CH3COOC2H5
D
C2H5COOCH3
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
When sodium ethanoate (CH\(_3\)COONa) is treated with concentrated tetraoxosulphate(VI) acid (H\(_2\)SO\(_4\)), a displacement reaction occurs. The strong mineral acid (H\(_2\)SO\(_4\)) reacts with the salt of the weaker organic acid to displace and liberate the organic acid, which is ethanoic acid (also known as acetic acid, CH\(_3\)COOH).
Source: Myschool Past Questions Archive (Record #44427)