JAMB - Chemistry (1985)

1
X + Y = Z is an equilibrium reaction. The addition of a catalyst?
Respuesta
(B)
increases the rate of change in concentrations of X, Y and Z
2
What is the formula of sodium gallate if gallium (Ga)shows an oxidation number of + 3?
Respuesta
(D)
NaGa(OH)₄
3
If the ONLY pollutants found in the atmosphere over a city are oxides of nitrogen, suspended lead compounds. carbon monoxide and high levels of methane, the probable source(s) of the pollution must be?
Respuesta
(B)
combustion of coal and automobile exhaust
4
A correct electrochemical series can be obtained from K, Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging?
Respuesta
(A)
Al and Mg
5
A certain industrial process is represented by the chemical equation 2A_(g) + B_(g) \(\to\) C_(g) + 3D_(g) \(\Delta\)H = X kJmol^-1. Which of the following conditions will favour the yield of the products?
Respuesta
(A)
increase in temperature, decrease in pressure
6
2MnO^-₄ + 10Cl^- + 16H⁺ → 2Mn²⁺ + 5Cl₂ + 8H₂O. Which of the substances serves as an oxidizing agent?
Respuesta
(D)
MnO^-₄
7
Which of the following metals will displace iron from a solution of iron(ll)tetraoxosulphate(lV)?
Respuesta
(D)
Zinc
8
In the reaction H2(g)O \(\to\) H2(g) + 1/2O2(g)

ΔH = -2436000 KJ, which of the following has no effect on the equilibrium position?
Respuesta
(A)
Adding argon to the system
9
Complete hydrogenation of ethyne yields?
Respuesta
(C)
ethane
10
Which of the following is used in the manufacture of bleaching powder?
Respuesta
(B)
Chlorine
11
A man suspected of being drunk is made to pass his breath into acidified potassium dichlormate solution. If his breath carries a significant level of ethanol, the final colour of the solution is?
Respuesta
(E)
green
12
When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to?
Respuesta
(E)
the bombardment of the pollen grains by molecules of water
13
The energy change (ΔH) for the reaction CO(g) + (1)/(2)O_2(g) → is?

(ΔHi(CO) = -110.4 kJ mol^-) (ΔHi(CO₂) = -393 kJ mol^-)
Respuesta
(C)
-282.9 kJ
14
Tetraoxosulphate (IV) ions are finally tested using?
Respuesta
(B)
acidified barium chloride
15
An organic compound decolourized acidified KMnO₄ solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be?
Respuesta
(C)
an alkene
16
Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula?
Respuesta
(C)
Na₂CO₃O
17
Which of the following substances is the most abundant in the universe?
Respuesta
(E)
Hydrogen
18
A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Compound X is?
Respuesta
(B)
an alkane
19
A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Y and Z are respectively?
Respuesta
(D)
CO₂ and H₂O
20
Which of the following compounds is NOT the correct product formed when the parent metals is heated in air?
Respuesta
(D)
Tri-iron tetroxide (Fe₃O₄)
21
The atomic number of an element whose cation, X2+, has the ground state electronic configuration 1s22s22p63s22p6 is?
Respuesta
(C)
20
22
When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains?
Respuesta
(E)
Ca(OH)₂
23
Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably?
Respuesta
(C)
Na₂S₂O₃.5H₂O
24
The process involved in the conversion of an oil into margarine is known as?
Respuesta
(A)
hydrogenation
25
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?
Respuesta
(E)
Pb₊₊
26
Which of the following roles does sodium chloride play in soap preparation? It
Respuesta
(D)
separates the soap from the glycerol
27
The function of sulphur during vulcanization rubber is to?
Respuesta
(C)
from chains which bind rubber molecules together
28
Figure 1 above shows part of the periodic Table which of the elements belongs to the p-block?
Respuesta
(D)
P, Q and R
29
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)
Respuesta
(A)
Y is twice as soluble as X
30
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
Respuesta
(B)
only 16 g of Y undissolved
31
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
Respuesta
(D)
2.0 moles
32
Use the above options to the question. The products formed on hydrolysis of
Respuesta
(C)
C
33
The oxidation of
Respuesta
(A)
2-butanone
34
The I.U.P.A.C name for the compound
Respuesta
(D)
4-methylpent-2-ene
35
Use the following option above to answer this question. Which of the following is the functional group of carboxylic acids?
Respuesta
(D)
D
36
Which of the following conduct electricity?
Respuesta
(B)
graphite
37
An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. The empirical formula of the compound is
Respuesta
(D)
C₆H₁₂O
38
0.499g 0f CuSO₄.xH₂O when heated to constant weight gave a residue of 0.346g. the value of x is? (Cu = 63.5, S = 32.0, O = 16, H = 1)
Respuesta
(D)
4.0
39
In the experiment, which of the following observations would suggest that a solid sample is a mixture? The
Respuesta
(C)
solid begins to melt at 573k but is not completely melted until 648k
40
Hydrogen diffuses through a porous plug
Respuesta
(E)
four times as fast as oxygen
41
Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound?
Respuesta
(C)
6.25 moles
42
3.0g of a mixture of potassium carbonate and potassium chloride were dissolved were dissolved in a 250cm\(^3\) standard flask. 25cm\(^3\) of this solution required 40.00cm\(^3\) of 0.1M HCl for neutralization. What is the percentage by weight of K\(_2\)CO\(_3\) in the mixture ? (K = 39, O = 16, C = 12)
Respuesta
(E)
92
43
Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.

Which of the above are NOT typical properties of alkalis?
Respuesta
(C)
i and iv
44
A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature?
Respuesta
(E)
4768.0k
45
Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because
Respuesta
(B)
hydrogen produced is oxidized to water