All questions of Electrolysis for JAMB Exam

• A:

  temperature only

• B:

  Concentration of electrolyte only

• C:

  Both a and b

• D:

  Density of the electrodes

The answer is c.

• a)
  E^θRed is positive
• b)
  ΔG^θ is positive
• c)
  ΔG^θ is negative
• d)
  E^θRed is negative.

• a)
  I
• b)
  !!
• c)
  ((
• d)
  II

• a)
  Velocity of K⁺ and NO₃^– are same
• b)
  Velocity of NO₃^– is greater than that of K⁺
• c)
  Velocity of K⁺ is greater than that of NO₃^–
• d)
  KNO₃ is highly soluble in water

• a)
  6 FE°cell
• b)
  3 FE°cell
• c)
  -2 FE°cell
• d)
  -6 FE°cell

The gas X at 1 atm is bubbled through a solution containing a mixture of 1 M Y^- and 1 M Z^- at 298 K.If the standard reduction potential

then,

• a)
  Y will oxidise X and not Z
• b)
  Y will oxidise Z and not X
• c)
  Y will oxidise both X and Z
• d)
  Z^- will reduce both X and Y

For the cell,  and for the cell Pt(H₂) | H⁺ (1M)| Ag,  

Thus E_cell for the

Ag|Ag⁺ (0.1M) || Zn²⁺ (0.1M) | Zn is  ....................and cell reaction is...............

• a)
  1.44 V ,spontaneous
• b)
  0.4 V ,spontaneous
• c)
  -1.44 V ,non-spontaneous
• d)
  -1.53 V ,non-spontaneous

• a)
  Boltzmann constant
• b)
  Faraday’s constant
• c)
  Gas constant
• d)
  Universal gas constant

• a)
  Increase [Cd²⁺] as well as [Cu²⁺] to 2.0 M
• b)
  Increase only [Cu²⁺] to 2.0 M
• c)
  Reduce only [Cd²⁺] to 0.1 M
• d)
  Decreases [Cd²⁺] to 0.1M and increases [Cu²⁺] to 1.0M

• a)
  Salt bridge
• b)
  Electrolyte
• c)
  Anode
• d)
  Cathode

• a)
  cell will discharge easily
• b)
  Cell reaction is spontaneous
• c)
  Cell reaction is non spontaneous
• d)
  Cell will work under standard conditions

• a)
  A>B>C
• b)
  Cannot be answered
• c)
  B>C>A
• d)
  A

• a)
  Hydrolysis
• b)
  Reduction
• c)
  Oxidation
• d)
  Neutralization

For the following cell with hydrogen electrodes at two different  pressure p₁ and p₂ 

 emf is given by

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  Reduction
• b)
  Neutralization
• c)
  Hydrolysis
• d)
  Oxidation

• a)
  Cell potential’ E _cell‘ becomes zero
• b)
  Equilibrium constant becomes equal to electrode potential
• c)
  Equilibrium constant becomes zero
• d)
  Cell potential ‘E _cell‘ becomes unity

• a)
  9 h
• b)
  4.5 h
• c)
  1 h
• d)
  3.0 h

• a)
  0.77 V , 0.826 V
• b)
  -0.826 V , -0.77 V
• c)
  -0.77 V ,-0.826 V
• d)
  0.00 V , 0.00 V

• a)
  Zn|zn²⁺||Cu²⁺|Cu
• b)
  Cu²⁺|Cu||Zn|zn²⁺
• c)
  Zn|zn²⁺||Cu|Cu²⁺
• d)
  Cu|Cu²⁺||zn²⁺|Zn

A concentration cell reversible to anion (Cl^-) is set up

   

cell reaction is spontaneous ,if 

• a)
  C₁ > C₂
• b)
  C₁ < C₂
• c)
  C₁ = C₂
• d)
  C₁ = 0

• a)
  Decreases to zero
• b)
  Increases
• c)
  Increases rapidly
• d)
  Do not change

• a)
  1.40 A
• b)
  1.27 A
• c)
  0.70 A
• d)
  0.14 A

• a)
  1 : 1
• b)
  2 : 1
• c)
  2 : 3
• d)
  4 : 3

• a)
  electrodes made of lead-lead oxide
• b)
  electrodes made of calcium-containing lead alloy
• c)
  non-aqueous solvents as medium
• d)
  platinum electrodes

• a)
  copper and zinc electrodes respectively
• b)
  zinc and copper electrodes respectively
• c)
  both occur at copper electrode respectively
• d)
  both occur at zinc electrode respectively

Consider the following cell reaction,

 E^°= 1.67 V

At [Fe²⁺] = 1 x 10^-3 M.  and pH = 3,the cell potential at 298 K is 

• a)
  1.47 V
• b)
  1.77 V
• c)
  1.87 V
• d)
  1.57 V

Two half-cells are given

For a spontaneous cell reaction, cell set up is    

• a)
  Ag| AgCI| KCI (0.2M) 11 KBr (0.001 M)| AgBr| Ag
• b)
  Ag| AgBr| KBr (0.001 M) 11 KCI (0.2 M) | AgCI | Ag
• c)
  Both (a) and (b)
• d)
  None of the above

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  salt bridge
• b)
  Electrolyte
• c)
  Anode
• d)
  Cathode

• a)
  In lead-storage battery,galvanic cell are linked in series
• b)
  Cathode and anode compartments are not seperated in a battery as oxidant and reductant both are solids
• c)
  Recharging of a storage battery is a non-spontaneous (ΔG^° > 0)
• d)
  All of the above

• a)
  386 kJ
• b)
  -386 kJ
• c)
  -193 kJ
• d)
  -572 kJ

• a)
  I , II
• b)
  I , III
• c)
  II , III
• d)
  I , II , III

• a)
  1.0 X 10^-12 M
• b)
  4.8 M
• c)
  3.3 X 10^-12 M
• d)
  9.6 M

• a)
  Zn plates out at the cathode
• b)
  Zn plates out at the anode
• c)
  H₂ gas is evolved at the anode
• d)
  O₂ gas is evolved at the anode

• a)
  cathode and oxidation taken place
• b)
  anode and oxidation takes place
• c)
  anode and reduction takes place
• d)
  cathode and reduction takes place

• a)
  Molar concentration of solution
• b)
  Cathodic plate
• c)
  Anodic plate
• d)
  All of these

• a)
  If salt-bridge is removed,potentials falls to zero
• b)
  Quinhydrone electrode is reversible to H⁺ ion
• c)
  Liquid-junction potential developed across the boundary of the two solutions of different concentration is minimised if concentrations cell are used
• d)
  Calomel electrode contains calcium chloride solution in contact with Pt electrode

• a)
  formation of l₂ (violet)
• b)
  formation of Br₂ (orange)
• c)
  formation of l₂ and Br₂ both
• d)
  formation of F₂ (colourless)

• a)
  Y > Z > X
• b)
  X > Y > Z
• c)
  Z > Y > X
• d)
  Z > X > Y

• a)
  LHS half-cell will increase
• b)
  RHS half-cell will increase
• c)
  both half-cell will increase
• d)
  both half-cell will decrease

• a)
  1.0 mol
• b)
  2.0 mol
• c)
  3.0 mol
• d)
  4.0 mol

• a)
  cathodic reaction, when oxygen gas which is dissolved in H₂O, is reduced to OH^-
• b)
  acid rain which oxidises metal to metal ion
• c)
  Both (a) and (b)
• d)
  None of the above

• a)
  Cu₂(OH)₂SO₄
• b)
  Cu(OH)₂(SO₄)₂
• c)
  Cu(OH)SO₄
• d)
  Cu(OH)(SO₄)₂

• a)
  P t(s)|H₂(g, 0.1 bar) | H⁺ (aq, 0.1 M) || Zn²⁺ (aq, 0.1 M)|
• b)
  P t(s)|H₂(g, 0.1 bar) | H⁺ (aq, 0.1 M) || Zn²⁺ (aq, 0.2 M)| Zn
• c)
  P t(s)|H₂(g, 0.1 bar) | H⁺ (aq, 0.1 M) || Zn²⁺ (aq, 1.0 M)| Zn
• d)
  P t(s)|H₂(g, 0.1 bar) | H⁺ (aq, 1.0 M) || Zn²⁺ (aq, 0.1 M)| Zn

• a)
  Electric current is used to drive a non-spontaneous reaction
• b)
  E_cell is positive and ΔG is negative
• c)
  Cations and anions are discharged at the cathode and anode respectively
• d)
  Overvoltage is responsible that a particular reaction takes place

• a)
  I , II , III
• b)
  I ,II
• c)
  II , III
• d)
  Only III

• a)
  610.00 A
• b)
  620.00 A
• c)
  617.8 A
• d)
  643.3 A

• a)
  Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
• b)
  Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
• c)
  Statement I is correct but Statement II is incorrect
• d)
  Statement II is correct but Statement I is incorrect