2013 - JAMB Chemistry Past Questions and Answers - page 2
11
If 24.4 g of lead (ll) trioxonitrate (V) were dissolved in 42 g of distilled water at 20oC; calculate the solubility of the solute in gdm-3.
A
581.000.
B
0.581
C
5.810
D
58.100
correct option: a
Users' Answers & Comments12
The solvent used for removing grease stain is
A
turpentine
B
ammonia solution
C
ethanol
D
solution of borax in water
correct option: b
Users' Answers & Comments13
In a water body, too much sewage leads to
A
a decrease in the temperature of the water which cause in death of aquatic animals
B
an increase in the number of aquatic animals in the water
C
an increase in the bacterial population which reduces the level of oxygen in the water
D
a decrease in the bacterial population which increases the level of oxygen in the water
correct option: c
Users' Answers & Comments14
10.0 dm3 of water was added to 2.0 mol dm-3 of 2.5dm3 solution of HCl. What is the concentration of the final solution in mol dm-3?
A
0.4
B
8.0
C
2.0
D
0.5
correct option: a
C1V1 = C2V2
C2 = \(\frac{C_1V_1}{V_2}\)
= \(\frac{2.0 \times 2.5}{12.5}\)
= 0.4mol/dm-3
Users' Answers & CommentsC2 = \(\frac{C_1V_1}{V_2}\)
= \(\frac{2.0 \times 2.5}{12.5}\)
= 0.4mol/dm-3
15
Three drops of a 1.0 mol dm-3 solution of HCl was added to 20 cm3 of a solution of pH6.4. The pH of the resulting solution will be
A
close to that of pure water
B
less than 6.4
C
greater than 6.4
D
unaltered
correct option: b
Users' Answers & Comments16
Which of the following substances is not a salt?
A
Aluminium oxide
B
Sodium hydrogentrioxosulphate (V)
C
Sodium trioxocarbonate (V)
D
Zinc chloride
correct option: a
Users' Answers & Comments17
An insoluble salt can be prepared by
A
the reaction of trioxocarbonate (V) with an acid
B
double decomposition
C
the action of dilute acid on an insoluble base
D
the reaction of metals with an acid
correct option: b
Users' Answers & Comments18
2H2O (l) + 2F2(g) → 4HF(aq) + O2(g).
In the reaction above, the substance that is being reduced is
In the reaction above, the substance that is being reduced is
A
O2(g)
B
H2O(l)
C
F2(g)
D
HF(aq)
correct option: c
F(2) + 2e \(\rightarrow\) 2F- x 2
2F2 + 4e \(\rightarrow\) 4F-
Users' Answers & Comments2F2 + 4e \(\rightarrow\) 4F-
19
In an electrochemical cell, polarization is caused by
A
chlorine
B
oxygen
C
tetaoxsulphate (Vl) acid
D
hydrogen
correct option: d
Users' Answers & Comments20
Calculate the volume in cm3 of oxygen evolved as s.t.p. when a current of 5 A is passed through acidified water for 193s
{F = 96500 Cmol-1, Molar volume of a gas at s.t.p. = 22.4 dm3}
{F = 96500 Cmol-1, Molar volume of a gas at s.t.p. = 22.4 dm3}
A
224.000 dm3
B
0.056 dm3
C
0.224 dm3
D
56.000 dm3
correct option: b
Q = 1 x t \(\implies\) Q = (5 x 193)C
Q = 965C
40H \(\implies\) 2H2O + O2 + 4e
4 X 96500C evolve 22.4 dm3 x 965
4 x 96500 = 0.056 dm3
Users' Answers & CommentsQ = 965C
40H \(\implies\) 2H2O + O2 + 4e
4 X 96500C evolve 22.4 dm3 x 965
4 x 96500 = 0.056 dm3