Electrolysis Generix Content - Electrolysis
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JAMB questions for "Chemistry :: Electrolysis"
Q1

Which of the following metals is purified commercially by electrolysis?

A

Zn

B

Fe

C

Sn

D

Cu

E

Answer: A

Electrolysis
Q2

What current will deposit 3.25g of zinc in 2 hours?

 

[Zn = 65, F = 96500 C mol-1]

A

3.25 A

B

2.00 A

C

1.34 A

D

0.67 A

E

Answer: C

Electrolysis
Q3

If a given quantity of electricity liberates 0.65g of Zn2+, what amount of Hg2+ would be liberated by the same quantity of current?

 

[Zn = 65, Hg = 201] 

A

1.00g

B

2.01g

C

4.02g

D

8.04g

E

Answer: C

Electrolysis
Q4

Which of the following reactions is endothermic?

A

C(s) + O2(g) → CO2(g)

B

CaO(s) + H2O(l) → Ca(OH)2(s)

C

C(s) + H2O(g) → CO(g) + H2(g)

D

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

E

Answer: B

Electrolysis
Q5

The reddish-brown rust on iron roofing sheets consists of 

A

FeO.H2O

B

Fe2O3.3H2O

C

Fe3O4.2H2O

D

Fe3+(2H2O)6

E

Answer: B

Electrolysis
Q6

The ion that will give a white precipitate with aqueous NaOH and soluble in excess of the base is 

A

Ca2+

B

Mg2+

C

Zn2+

D

Cu2+

E

Answer: C

Electrolysis
Q7
The idea of planatery electrons was that of 
A
Rutherford
B
Thompson
C
Bohr
D
Dalton
E

Answer: A

Electrolysis
Q8
In the electrolysis of CuSO4(aq) using platinum electrodes, the reaction at the anode is
A
4H+ + 4e- → 2H2
B
4OH- - 4e- → 2H2O +O2
C
2OH- - 2e- → 2OH
D
2OH- + 2OH- → 2H2O + O2
E

Answer: B

Electrolysis
Q9
5SO2(aq) + 2KMnO4(aq) + 2H2O(l) → K2SO4(aq) + 2MnSO4(aq) + 2H2SO4(aq)   In the reaction, the products gives a
A
purple solution
B
purple precipitation
C
colourless precipitate
D
colourless solution
E

Answer: D

Electrolysis
Q10
The pressure of 100 cm3 of oxygen at 35oC is 750 mm Hg. What will be the volume of the gas if the pressure is reduced to 100 mm Hg without changing the temperature?
A
850 cm3
B
750 cm3
C
650 cm3
D
580 cm3
E

Answer: B

Electrolysis
Q11
A concentrated solution containing H+, Cu2+, OH- and Cl- was electrolysed using platinum electrodes. The ion that will be discharged at the cathode is 
A
OH-
B
CI-
C
Cu2+
D
H+
E

Answer: C

Electrolysis
Q12
What volume of 0.5 mol dm-3 H2SO4 will exactly neutralize 20cm2 of 0.1 mol dm-3 NaOH solution?
A
5.0cm3
B
6.8cm3
C
8.3cm3
D
2.0cm3
E

Answer: D

Electrolysis
Q13
In the reaction above, zinc has been 
A
displaced 
B
oxidized
C
reduced
D
deomposed
E

Answer: C

Electrolysis
Q14
In the electrolysis of brine, the anode is
A
zinc
B
platinum
C
carbon
D
copper
E

Answer: C

Electrolysis
Q15
In the electrolysis of a concentrated solution of sodium chloride using inert electrodes, which of the following ions are discharged at the cathode and anode respectively?
A
H+ and Cl-
B
H+ and OH-
C
Na+ and OH-
D
Na+ and Cl-
E

Answer: A

Electrolysis
Q16
Which of the following is an electrolyte?
A
Mercury
B
Alcohol
C
Sodium acetate solution
D
Solid potassium hydroxide
E

Answer: C

Electrolysis
Q17
l.    H  = 1s1ll.   N  = 1s22s22p3lll.  O = 1s22s22p4lV.  Zn =1s22s22p63s23p64s23d10     From the above, which of the following pairs is likely to be paragmagnetic?
A
lll and lV
B
l and ll
C
l and lll
D
l and lV
E

Answer: D

Electrolysis
Q18
What is the percentage by mass of oxygen in Al2(SO4)3.2H2O?   [Al = 27, S = 32, H = 1, O = 16]
A
59.25%
B
50.79%
C
25.39%
D
14.29%
E

Answer: A

Electrolysis
Q19
146C → x +   X in the equation above represents 
A
126C
B
125B
C
147N
D
136C
E

Answer: C

Electrolysis
Q20
Which of the following statements is true of a proton?
A
The mass of a proton is 1840 times the mass of an electron
B
The total mass of the proton in a particular nucleus is always half the nuclear mass
C
The mass of a proton is one twelfth the molar mass of carbon
D
The mass of a proton is 1.0008g
E

Answer: D

Electrolysis
Q21
Which of the following polymers is suitable for packaging and electrical insulation?
A
polyamide
B
polyethene
C
polycarbonate
D
polystyrene
E

Answer: B

Electrolysis
Q22
Which of the following gives a precipate when treated with NaOH solution?
A
AlCl3
B
NH4Cl
C
CH3COONa
D
Na2CO3
E

Answer: A

Electrolysis
Q23
When dissolved in water, NaOH flakes show
A
an endothermic change
B
an exothermic change
C
a slow reaction
D
a rapid reaction
E

Answer: B

Electrolysis
Q24
The product of the electrolysis of dilute sodium hydroxide using platimun electrodes are
A
hydrogen and oxygen gas
B
water and hydrogen gas
C
water and sodium metal
D
sodium metal and oxygen gas
E

Answer: A

Electrolysis
Q25
What amount of mercury would be liberated if the same quantity of electricity that liberates 0.65g of zinc is applied?   [Zn = 65, Hg = 201]
A
2.01 g
B
1.00 g
C
4.02 g
D
8.04 g
E

Answer: C

Electrolysis
Q26
As the concentration of an electrolyte reduces, the conductivity
A
decreases 
B
increases
C
reduces to zero
D
is unaffected
E

Answer: A

Electrolysis
Q27
3Cu(s) + 8HNO3(aq) → 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g).   In the equation above, copper is
A
a base
B
an oxidizing agent
C
a reducing agent
D
an electron acceptor
E

Answer: C

Electrolysis
Q28
A particle that contains 9 protons, 10 neutrons and 10 electrons is a 
A
positive ion
B
neutral atom of a metal
C
neutral atom of a non-metal
D
negative ion
E

Answer: D

Electrolysis
Q29
˝Zn2+(aq) + e- → ˝Zn(s)   In the reaction above, calculate the quantity of electricity required to discharge zinc   [F = 96 500 C mol-1]
A
0.965 x 104C
B
4.820 x 104C
C
9.650 x 104C
D
48.200 x 104C
E

Answer: C

Electrolysis
Q30
Given that M is the mass of substance deposited in an electrolysis and Q the quantity of electricity consumed, then Faraday's law can be written as 
A
M = Z/Q
B
M = Q/Z
C
M = Z/2Q
D
M = QZ
E

Answer: D

Electrolysis
Q31
MnO4(aq) + 8H+(aq) + Y → Mn2+(aq) + 4H2O(l)    Y in the equation above represents
A
2e-
B
3e-
C
5e-
D
7e-
E

Answer: C

Electrolysis
Q32
The knowledge of half-life can be used to
A
create an element 
B
detect an element 
C
split an element
D
irradiate an element
E

Answer: B

Electrolysis
Q33
The electron configuration of 22X2+ ion is
A
1s22s22p63s23p64s23d2
B
1s22s22p63s23p64s23d1
C
1s22s22p63s23p2
D
1s22s22p63s23p64s2 
E

Answer: D

Electrolysis
Q34
In order to remove one electron from a 3s orbital a gaseous sodium atom, about 496 kJ mol-1 of energy is required. This energy is referred to as 
A
electron affinity
B
ionization energy
C
activation energy
D
electronegativity
E

Answer: B

Electrolysis
Q35
When a current 1 was passed through an electrolyte solution for 140 minutes, a mass Xg of a univalent mass of the metal will be deposited when a current 21 is passed through the solution for 10 minutes?
A
X/4 g
B
X/2 g
C
2X g
D
4X g
E

Answer: B

Electrolysis
Q36
Which of the following statements is true of the electrochemical series?
A
Electropositivity of the metals increase down the series.
B
Electropositivity of the non metals decrease down the series.
C
Electronegativity of non metals increases down the series.
D
Electropositivity of metals decrease down the series.
E

Answer: C

Electrolysis
Q37
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?   [F = 96 500C mol-1]
A
24 125 coulombs
B
48 250 coulombs
C
72 375 coulombs
D
96 500 coulombs
E

Answer: B

Electrolysis
Q38
1s22s22p63s23p63d74s2. An element with the electron configuration above is
A
non-metal
B
metal
C
transition element
D
group two element
E

Answer: C

Electrolysis
Q39
Given that electronegativity increases cross a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?
A
HF(g)
B
NH3(aq)
C
CH4(g)
D
HCl(g)
E

Answer: A

Electrolysis
Q40
Mg(s) + 2HCI(aq) → MgCl2(aq) + H2(g).   From the equation above the mass of magnesium required to react with 250 cm3  of 0.5 M HCl is 
A
0.3 g
B
1.5 g
C
2.4 g
D
3.0 g
E

Answer: B

Electrolysis
Q41
Mg2+(aq) + 2e-(aq) → Mg(s)Eo(volts) = -2.370Zn2+(aq) + 2e-(aq) → Zn(s)Eo(volts) = -0.763Cd2+(aq) + 2e-(aq) → Cd(s)Eo(volts) = -0.403Cu2+(aq) + 2e-(aq) → Cu(s)Eo(volts) = -0.340   In the electrochemical series above, the strongest reducing agents is
A
Cu(s)
B
Cd(s)
C
Zn(s)
D
Mg(s)
E

Answer: D

Electrolysis
Q42
1.2 F of electricity are passed through electrolytic cells containing Na+, Cu2+ and Al3+ in series. How many moles of each metal would be formed at the cathode of each cell?
A
0.6 moles of Na, 1.2 moles of Al.
B
1.2 moles of Na, 0.6 moles of Cu and 0.4 mole of Al
C
1.2 moles of Na, 2.4 moles of Cu and 2.4 moles of Al
D
1.2 moles of Na, 2.4 moles of Cu and 3.6 moles of Al
E

Answer: D

Electrolysis
Q43
What mass of gold is deposited during the elctrolysis of gold (III) tetraoxosulphate (VI) when a current of 15A is passed for 193 seconds?   [Au = 97, F = 96500C mol-1]
A
1.97 g
B
3.94 g
C
5.91 g
D
19.70 g
E

Answer: A

Electrolysis
Q44
The lines observed in the simple hydrogen spectrum are due to emission of
A
electrons from the atom
B
energy by proton transition
C
energy by electron transition
D
neutrons from the atom
E

Answer: C

Electrolysis
Q45
The electron configurations of two elements with similar chemical properties are represented by
A
1s22s22p5 and 1s22s22p4
B
1s22s22p4 and 1s22s22p63s1
C
1s22s22p63s1 and 1s22s1
D
1s22s22p4 and  1s22s1
E

Answer: C

Electrolysis
Q46
Given that 15.00cm3 of H2SO4 was required to completely neutralize 25.00cm3 of 0.125 mol dm-3 NaOH, calculate the molar concentration of the acid solution
A
0.925 mol dm-3
B
0.156 mol dm-3
C
0.104 mol dm-3
D
0.023 mol dm-3
E

Answer: C

Electrolysis
Q47
When platinum electrodes are used during the electrolysis of copper (II) tetraoxosulphate (VI) solution, the solution gets professively
A
acidic
B
basic
C
neutral
D
amphoteric
E

Answer: A

Electrolysis
Q48
How many faradays of electricity are required to deposit 0.20 mole of nickel, if 0.10 faradays of elcricity deposited 2.98g of nickel during electrolysis of its aqueous solution?   [Ni = 58.7, 1F = 96 500 C mol-1]
A
0.20
B
0.30
C
0.40
D
0.50
E

Answer: C

Electrolysis
Q49
A particle that contains 8 protons, 9 neutrons and 7 electrons could be written as
A
168O
B
178O+
C
179O+
D
179O-
E

Answer: B

Electrolysis
Q50
In the process of silver-plating a metal M, the metal M is the
A
anode and a direct current is used
B
cathode and an alternating current is used
C
anode and an alternating current is used
D
cathode and a direct current is used
E

Answer: D

Electrolysis
Q51
How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulphate (VI)?   [F = 96 500 C mol-1]
A
0.5
B
1.0
C
1.5
D
3.0
E

Answer: C

Electrolysis
Q52
2CI-(aq) → Cl2(g) + 2e-(aq).  The above half cell reaction occuring at the anode during the electrolysis of dilute ZnCl2 solution is
A
ionization
B
oxidation
C
reduction
D
recombination
E

Answer: B

Electrolysis
Q53
In the extraction of iron in the blast furnance, limestone is used to
A
release CO2 for the reaction
B
reduce the iron ore
C
increase the strenght of the iron
D
remove impurities
E

Answer: D

Electrolysis
Q54
Which of the following compounds will impart a brick-red colour to a non-luminous Bunsen flame?
A
NaCl
B
LiCl
C
CaCl2
D
MgCl2
E

Answer: C

Electrolysis
Q55
Which of the following atoms represents deuterium?   No of protons             No of neutrons             No of electrons
A
1                                     0                                  0
B
1                                    0                                     1
C
1                                  1                                     1
D
1                                 2                                       1
E

Answer: C

Electrolysis
Q56
What volume of oxygen measured at s.t.p. would be liberated on electrolysis of concentrated copper (II) chloride if the crude copper is   [Molar Volume of gas = 22.4 dm3, F = 96500 C mol-1]
A
22.4 dm3
B
11.2 dm3
C
1.12 dm3
D
0.560 dm3
E

Answer: D

Electrolysis
Q57
In an electrolytic set-up to protect iron from corrosion, the iron is
A
made the cathode
B
made the anode
C
used with a metal of lower electropositive potential
D
initially coated with tin.
E

Answer: D

Electrolysis
Q58
Crude copper could be purified by the electrolysis of concentrated copper (II) chloride if the crude copper is
A
made both the anode and cathode
B
made the cathode
C
made the anode
D
dissolved in the solution
E

Answer: C

Electrolysis
Q59
During the electrolysis of a salt of a metal M, a current of 0.5. A flows for 32 minuted 10 seconds and deposits 0.325 g of M. What is the charge on the metal ion?   [M = 65, IF = 96,500 C per mole of electron]
A
1
B
2
C
3
D
4
E

Answer: B

Electrolysis
Q60
Which of the following reactions occurs at the anode during the electrolysis of a very dilute aqueous solution of sodium chloride
A
OH- - e → OH
B
Cl- - e- → Cl
C
OH- + Cl- → HCl + O2-
D
           HgNa+ - e → Na/Hg amalgam
E

Answer: A

Electrolysis