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Chemistry
UTME / JAMB 1985
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
The process involved in the conversion of an oil into margarine is known as?
A
hydrogenation
B
condensation
C
pyrolysis
D
dehydration
E
cracking
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Margarine is an inexpensive alternate to butter, made from oil or a combination of oils through the process of hydrogenation.
Source: Myschool Past Questions Archive (Record #14133)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH\(_3\) (iii) with dilute HCl. The cation present in the inorganic salt is?
A
Na+
B
Ca++
C
Zn++
D
Al+++
E
Pb++
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
Ca\(^{2+}\) (calcium ions) do not form a precipitate that is soluble in excess NaOH, or in dilute HCl, but they do form a white precipitate with NaOH that is insoluble in excess NaOH and in NH\(_3\).
Zn\(^{2+}\) ions form a white precipitate (Zn(OH)₂) with sodium hydroxide (NaOH) that is soluble in excess NaOH and also soluble in excess ammonia (NH₃), forming a complex ion, but insoluble in dilute HCl.
Adding NaOH to Al\(^{3+}\) solution initially forms a white precipitate of Al(OH)₃, which is then soluble in excess NaOH, but the precipitate remains insoluble in NH₃ and dilute HCl.
Pb\(^{2+}\) ions form a white precipitate (lead(II) hydroxide, Pb(OH)\(_2\)) with both sodium hydroxide (NaOH) and aqueous ammonia (NH\(_3\)), but the precipitate is soluble in excess NaOH, but insoluble in excess NH\(_3\). It's also insoluble in dilute HCl.
Both Pb\(^{2+}\) and Al\(^{3+}\) form white precipitates soluble in excess NaOH and insoluble in NH\(_3\) and dilute HCl. However, lead(II) chloride, PbCl\(_2\) is slightly soluble in cold HCl and more soluble in hot HCl while AlCl\(_3\) is soluble in HCl.
Since the precipitate is described as insoluble in dilute HCl, Pb\(^{2+}\) is the more likely candidate.
Source: Myschool Past Questions Archive (Record #14134)
Chemistry
UTME / JAMB 1985
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Which of the following roles does sodium chloride play in soap preparation? It
A
reacts with glycerol
B
purifies the soap
C
accelerates the decomposition of the fat or oil
D
separates the soap from the glycerol
E
converts the fatty acid to its sodium salt
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 #14135)
Chemistry
UTME / JAMB 1985
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The function of sulphur during vulcanization rubber is to?
A
act as catalyst for the polymerization of rubber molecules
B
convert rubber from thermosetting to thermo plastics polymer
C
from chains which bind rubber molecules together
D
break down rubber polyer
E
shorten the chain length of rubber polyer
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 #14136)
Chemistry
UTME / JAMB 1985
Periodic Table & Periodicity
Diagram
Figure 1 above shows part of the periodic Table which of the elements belongs to the p-block?
Attached Figure / Diagram
A
S, T and U
B
V, W and X
C
S and T only
D
P, Q and R
E
V, W, X and S
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 #31336)
Chemistry
UTME / JAMB 1985
Water, Solutions & Solubility
Diagram
Solution
The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. At room temperature (300 K)
Attached Figure / Diagram
A
Y is twice as soluble as X
B
X is twice as soluble as Y
C
X and Y are soluble to the same extent
D
X is three times as soluble as Y
E
Y is three times as soluble as X
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
From the given graph, when properly traced At room temperature (300 K) Y is twice as soluble as X
Source: Myschool Past Questions Archive (Record #31340)
Chemistry
UTME / JAMB 1985
Water, Solutions & Solubility
Diagram
Solution
The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. If 80 g each of X and Y are taken up in 100 g of water at 353 K we shall have
Attached Figure / Diagram
A
only 10g of X undissolved
B
only 16 g of Y undissolved
C
10 g of X and 16 g of Y undissolved
D
all X and Y dissolved
E
all X and Y undissolved
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
For salt X, from the graph, 80g of X dissolves by 349K, so by 353K, all 80g of X is dissolved totally in 100g of water.
For salt Y, from the graph, 64g of Y dissolves by 353K, so (80-64)g of Y is left undissolved. This is 16g of Y left undissolved at that temperature.
Source: Myschool Past Questions Archive (Record #31343)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
Diagram
Solution
The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. If the molar mass of X is 36 g, the number of moles of X dissolved at 343 K is
Attached Figure / Diagram
A
0.2 moles
B
0.7 moles
C
1.5 moles
D
2.0 moles
E
3.0 moles
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The molar mass of x = 36g. At 343k, 72g of x dissolved
Molarity of x = \(\frac{72}{36}\) = 2.00moles.
Source: Myschool Past Questions Archive (Record #31344)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
Diagram
Use the above options to the question. The products formed on hydrolysis of
Attached Figure / Diagram
A
A
B
B
C
C
D
D
E
E
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 #31345)
Chemistry
UTME / JAMB 1985
Oxidation, Reduction & Redox Reactions
Diagram
Solution
The oxidation of
Attached Figure / Diagram
A
2-butanone
B
2-butanal
C
butane
D
butanoic acid
E
3-butanal
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Generally, oxidation of secondary alcohol yields Alkanone or Ketone. The structural formula of the compound above is 2-butanol.
Oxidation of 2-butanol, a secondary alcohol, yields 2-butanone (also known as methyl ethyl ketone), a ketone. This reaction typically occurs using oxidizing agents like sodium dichromate (Na\(_2\)Cr\(_2\)O\(_7\)) and sulphuric acid, or other oxidizing agents such as potassium permanganate (KMnO\(_4\)).
Source: Myschool Past Questions Archive (Record #31346)
Chemistry
UTME / JAMB 1985
Organic Chemistry I: Hydrocarbons & Crude Oil
Diagram
Solution
The I.U.P.A.C name for the compound
Attached Figure / Diagram
A
2-methyl-3-pentene
B
4-methyl-2-pentane
C
2-methyl-2-pentene
D
4-methylpent-2-ene
E
2-methyl-3-pentane
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
the IUPAC name of the given compound is 4 - methyl pent- 2- ene.
Source: Myschool Past Questions Archive (Record #31348)
Chemistry
UTME / JAMB 1985
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Diagram
Use the following option above to answer this question. Which of the following is the functional group of carboxylic acids?
Attached Figure / Diagram
A
A
B
B
C
C
D
D
E
E
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 #31351)
Chemistry
UTME / JAMB 1985
Electrolysis & Electrochemical Cells
Solution
Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs)
A
0.457g
B
0.500g
C
0.882g
D
0.914g
E
1.00g
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Time = 2hrs = 120mins = 120 x 60secs =7200secs.
current = 0.193amps
Quantity of electricity = 7200 x 0.193 = 1389.6
2 x 96,500 deposits 63.5 gms of Cu
1389.6 will deposit \(\frac{63.5 \times 1389.6}{2 \times 96500}\)
= 0.457g
Source: Official Exam / Past Question Archive
Chemistry
UTME / JAMB 1985
Non-Metals & Their Compounds
Which of the following conduct electricity?
A
sulfur
B
graphite
C
diamond
D
red phosphorus
E
yellow phosphorus
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 #44464)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. The empirical formula of the compound is
A
C8H22O3
B
C6H10O3
C
C12H12O
D
C6H12O
E
C3H6O
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
carbon = 72%, hydrogen = 12%, 16%
Dividing by the atomic weight we have for C = \(\frac{5}{1}\) = 6
H = \(\frac{12}{1}\) = 12
O = \(\frac{16}{16}\) = 1
Divide by the smallest number, we have = \(\frac{6}{1}\) = 6
H = \(\frac{12}{1}\) = 12
O = \(\frac{1}{1}\) = 1
The formula is C6H12O
Source: Myschool Past Questions Archive (Record #44469)