JEE Chemistry Electrochemistry MCQs Set A

Question: Which of the following statements is incorrect regarding electrochemistry?

• a)  The demerit associated with electrochemical methodsis that they are more polluting. Thus they are ecodestructive.
• b) Electrochemical reactions are more energy efficient and less polluting
• c) It is the study of production of electricity from energy released during spontaneous chemical reactions
• d) None of these

Answer:  The demerit associated with electrochemical methodsis that they are more polluting. Thus they are ecodestructive.

Question: What flows in the internal circuit of a galvanic cell?

• a) Ions
• b) Electricity
• c) Electrons
• d) Atoms

Answer: Ions

Question: Which of the following statements about galvanic cell is incorrect

• a) anode is positive
• b) oxidation occurs at the electrode with lower reduction potential
• c) cathode is positive
• d) reduction occurs at cathode

Answer: anode is positive

Question: Reaction that takes place at graphite anode in dry cell is

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: In which of the following conditions salt bridge is not required in a galvanic cell?

• a) When both the electrodes are dipped in the same electrolytic solution
• b) Electrolytic solutions used in both the half cells are of same concentration
• c) When distance between oxidation half cell and reduction half cell is negligible
• d) When galvanic cell is used in geyser

Answer: When both the electrodes are dipped in the same electrolytic solution

Question: Which device converts chemical energy of a spontaneous redox reaction into electrical energy?

• a) Both
• b) Daniell cell
• c) Galvanic cell
• d) None of these

Answer: Both

Question: Which one is not called a anode reaction from the following?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of the above representations

Answer:

Question:

• a) Daniel cell
• b) Faraday cell
• c) Weston cell
• d) Calomel cell

Answer: Daniel cell

Question: The tendency of an electrode to lose electrons is known as

• a) oxidation potential
• b) electrode potential
• c) reduction potential
• d) e.m.f.

Answer: oxidation potential

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Given that the standard reduction potentials for M⁺/M and N⁺/N electrodes at 298 K are 0.52 V and 0.25 V respectively. Which of the following is correct in respect of the following electrochemical cell ? M/M⁺ | | N⁺/N

• a) The standard EMF of the cell is – 0.27 V.
• b) The overall cell reaction is a spontaneous reaction
• c) The standard EMF of the cell is 0.77 V
• d) The standard EMF of the cell is – 0.77 V.

Answer: The standard EMF of the cell is – 0.27 V.

Question: The difference between the electrode potentials of two electrodes when no current is drawn through the cell is called _________.

• a) Cell emf
• b) Cell voltage
• c) Cell potentials
• d) Potential difference

Answer: Cell emf

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) (i) and (ii)
• b) (ii), (iii) and (iv)
• c) (ii), (iii) and (iv)
• d) (iii) and (iv)

Answer: (i) and (ii)

More Questions...............................

Question: The reference electrode is made by using

• a) Hg₂Cl₂
• b) CuSO₄
• c) ZnCl₂
• d) None of these

Answer: Hg₂Cl₂

Question: The standard hydrogen electrode potential is zero, because

• a) electrode potential is considered as zero
• b) hydrogen atom has only one electron
• c) None of these
• d) hydrogen oxidized easily

Answer: electrode potential is considered as zero

Question: Without losing its concentration ZnCl₂ solution cannot be kept in contact with

• a) Al
• b) Ag
• c) Au
• d) Pb

Answer: Al

Question:

• a) Fe³⁺
• b) [Fe(CN)₆]^4–
• c) Fe²⁺
• d) None of these

Answer: Fe³⁺

Question: Standard electrode potential of three metals X, Y and Z are – 1.2 V, + 0.5 V and – 3.0 V, respectively. The reducing power of these metals will be :

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

Answer:  Z > X > Y

Question: Standard electrode potential for Sn⁴⁺ / Sn²⁺ couple is + 0.15 V and that for the Cr³⁺ / Cr couple is – 0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be

• a) + 0.89 V
• b) + 1.83 V
• c) + 1.19 V
• d) + 0.18 V

Answer: + 0.89 V

Question :

• a) F₂ and I^–
• b) Br² and Cl^–
• c) Cl₂ and I₂
• d) None of these

Answer: F₂ and I^–

Question:

• a) 1.10 V
• b) 0.84 V
• c) 0.42 V
• d) 1.34 V

Answer: 1.10 V

Question: The oxidation potentials of A and B are +2.37 and +1.66 V respectively. In chemical reactions

• a) A will replace B
• b) A will be replaced by B
• c) A will not replace B
• d) A and B will not replace each other

Answer:  A will replace B

Question: A smuggler could not carry gold by depositing iron on the gold surface since

• a) gold has higher reduction potential than iron
• b) gold has lower reduction potential than iron
• c) iron rusts
• d) gold is denser

Answer: gold has higher reduction potential than iron

Question: Which of the following statement is not correct about an inert electrode in a cell ?

• a) It provides surface for redox reaction
• b) It provides surface for conduction of electrons
• c) It provides surface either for oxidation or for reduction reaction.
• d) It does not participate in the cell reaction

Answer: It provides surface for redox reaction

Question: Which of the following statement is not correct about an inert electrode in a cell ?

• a) It provides surface for redox reaction
• b) It provides surface for conduction of electrons
• c) It provides surface either for oxidation or for reduction reaction.
• d) It does not participate in the cell reaction

Answer: It provides surface for redox reaction

Question:

• a) decreases the cell emf
• b) alters the pH of the solution
• c) increases the current flow
• d) increases cell emf

Answer: decreases the cell emf

Question: The standard e.m.f. of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25°C. The equilibrium constant of the reaction would be (Given F = 96500 C mol^–1; R = 8.314JK^–1mol^–1)

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: The value of electrode potential (10^–4 M) H⁺ | H₂(1 atm) | Pt at 298 K would be

• a) – 0.236 V
• b) + 0.236 V
• c) + 0.404 V
• d) – 0.476 V

Answer: – 0.236 V

Question: According to Nernst equation, which is not correct if Q = K_c

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: The standard emf of a cell, involving one electron change is found to be 0.591 V at 25°C. The equilibrium constant of the reaction is (F = 96500 C mol^–1)

• a) 1.0 × 10¹⁰
• b) 1.0 × 10¹
• c) 1.0 × 10⁵
• d) 1.0 ×10³⁰

Answer: 1.0 × 10¹⁰

Question:

• a) [Cu²⁺] is increased
• b) [Zn²⁺] is increased
• c) [Cu²⁺] is decreased
• d) surface area of anode is increased

Answer: [Cu²⁺] is increased

Question:

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

Answer: 1.57 V

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) – 0.79
• b) – 0.70
• c) + 0.73
• d) – 0.82

Answer: – 0.79

Question:

• a) decreases by a small fraction
• b) increases but less than double
• c) halved
• d) doubled

Answer:  decreases by a small fraction

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) 10³⁷
• b) 10¹⁷
• c) 10^–37
• d) 10^–17

Answer:  10³⁷

Question:

• a) 0.26 V
• b) 1.2 V
• c) 0.53 V
• d) –0.53 V

Answer: 0.26 V

Question: If 0.01 M solution of an electrolyte has a resistance of 40 ohms in a cell having a cell constant of 0.4 cm^–1, then its molar conductance in ohm^–1 cm² mol^–1 is

• a) 10³
• b) 10⁴
• c) 10²
• d) 10

Answer:  10³

Question: Specific conductance of a 0.1 N KCl solution at 23ºC is 0.012 ohm^–1 cm^–1. Resistance of cell containing the solution at same temperature was found to be 55 ohm. The cell constant is

• a) 0.66 cm^–1
• b) 660 cm^–1
• c) 0.0616 cm^–1
• d) 6.60 cm^–1

Answer: 0.66 cm^–1

Question: The unit of equivalent conductivity is

• a) ohm^–1 cm² (g equivalent)^–1
• b) ohm cm² (g equivalent)
• c) ohm cm
• d) S cm^–2

Answer:  ohm^–1 cm² (g equivalent)^–1

Question: The resistance of 0.01 N solution of an electrolyte was found to be 220 ohm at 298 K using a conductivity cell with a cell constant of 0.88cm^–1. The value of equivalent conductance of solution is –

• a) 400 mho cm² g eq^–1
• b) 419 mho cm² g eq^–1
• c) 295 mho cm² g eq^–1
• d) None of these

Answer: 400 mho cm² g eq^–1

Question: Specific conductance of 0.1 M HNO₃ is 6.3×10^–2 ohm^–1 cm^–1. The molar conductance of the solution is

• a) 630 ohm^–1 cm²
• b) 100 ohm^–1 cm²
• c) 515 ohm^–1 cm²
• d) 6300 ohm^–1 cm²

Answer: 630 ohm^–1 cm²

Question: The specific conductance of a 0.1 N KCl solution at 23°C is 0.012 ohm^–1cm^–1. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be

• a) 0.66 cm^–1
• b) 1.12 cm^–1
• c) 0.142 cm^–1
• d) 0.918 cm^–1

Answer:  0.66 cm^–1

Question: The unit of specific conductivity is

• a) ohm^–1 cm^–1
• b) ohm cm^–2
• c) ohm cm^–1
• d) ohm^–1 cm

Answer: ohm^–1 cm^–1

Question: Which of the following solutions of KCl will have the highest value of specific conductance?

• a) 1.0 N
• b) 0.1 N
• c) 1.0 ×10^–2N
• d) 1.0 ×10^–3N

Answer: 1.0 N

Question: The cell constant of a conductivity cell ___________.

• a) remains constant for a cell
• b) changes with temperature of electrolyte
• c) changes with change of concentration of electrolyte
• d) changes with change of electrolyte

Answer: remains constant for a cell

Question:

• a) (i), (ii) and (iv)
• b) (i), (ii) and (iii)
• c) (ii) and (iii)
• d) (iii) only

Answer: (i), (ii) and (iv)

Question: On which of the following magnitude of conductivity does not depends?

• a) Mass of the material
• b) Temperature
• c) Nature of material
• d) Pressure

Answer:  Mass of the material

Question: Which of the following expression correctly represents molar conductivity?

• a) All of these
• b)

  

• c)

  

• d)

  

Answer: All of these

Question:

• a) 390.7
• b) 517.2
• c) 217.5
• d) 552.7

Answer: 390.7

Question: Kohlrausch’s law states that at

• a) infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte
• b) infinite dilution, each ion makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte
• c) infinite dilution each ion makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte
• d) finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte.

Answer: infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  At 25°C, the molar conductance at infinite dilution for the strong electrolytes NaOH, NaCl and BaCl2 are 248 × 10^–4, 126 × 10^–4 and 280 × 10^–4 Sm2mol^–1 respectively

• a) 524 × 10^–4
• b) 262 × 10^–4
• c) 52.4 × 10^–4
• d) 402 × 10^–4

Answer: 524 × 10^–4

Question:

• a) 388.8 ohm^–1cm²gmeq^–1
• b) 289.5 ohm^–1cm²gmeq^–1
• c) Both
• d) None of these

Answer: 388.8 ohm^–1cm²gmeq^–1

Question:  At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^-1 cm²mol^-1 and at infinite dilution its molar conductance is 238 ohm^-1 cm² mol^-1. The degree or ionisation of ammonium hydroxide at the same concentration and temperature is:

• a) 4.008%
• b) 2.080%
• c) 20.800%
• d) 40.800%

Answer: 4.008%

Question:

The electrical properties and their respective SI units are given below. Identify the wrongly matched pair.

• a)

  

  

• b)

  

  

• c)

  

     

• d) None of these

Answer:

Question: The ion of least limiting molar conductivity among the following is

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) 130 S cm² mol^–1
• b) 260 S cm² mol^–1
• c) 65 S cm² mol^–1
• d) 187 S cm² mol^–1

Answer: 130 S cm² mol^–1

Question: On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be

• a) oxygen
• b) Sulphur dioxide
• c) hydrogen
• d) hydrogen sulphide

Answer: oxygen

Question: If 0.5 amp current is passed through acidified silver nitrate solution for 100 minutes. The mass of silver deposited on cathode, is (eq.wt.of silver nitrate = 108)

• a) 3.3575 g
• b) 6.3575 g
• c) 2.3523 g
• d) 5.3578 g

Answer:  3.3575 g

Question:

• a) 5.49 × 10⁷ C
• b) 5.49 × 10⁴ C
• c) 5.49 × 10¹ C
• d) 1.83 × 10⁷ C

Answer: 5.49 × 10⁷ C

Question: Which of the following is the use of electrolysis

• a) Both
• b) Electrorefining
• c) Electroplating
• d) None of these

Answer: Both

Question: An electrolytic cell contains a solution of Ag₂SO₄ and has platinum electrodes. A current is passed until 1.6 gm of O₂ has been liberated at anode. The amount of silver deposited at cathode would be

• a) 21.60 gm
• b) 1.6 gm
• c) 107.88 gm
• d) 0.8 gm

Answer: 21.60 gm

Question: When 9650 coulombs of electricity is passed through a solution of copper sulphate, the amount of copper deposited is (given at. wt. of Cu = 63.6

• a) 3.18 g
• b) 63.6g
• c) 0318g
• d) 31.8g

Answer: 3.18 g

Question:

• a) 1.93 × 10⁴
• b) 1.93 × 10⁵
• c) 9.65 × 10⁴
• d) 9.65 × 10⁵

Answer: 1.93 × 10⁴

Question: A silver cup is plated with silver by passing 965 coulombs of electricity. The amount of Ag deposited is

• a) 1.08 g
• b) 9.89 g
• c) 107.89 g
• d) 1.0002 g

Answer: 1.08 g

Question: The number of coulombs required to reduce 12.3 g of nitrobenzene to aniline is

• a) 57900 C
• b) 5790 C
• c) 115800 C
• d) None of these

Answer: 57900 C

Question: The amount of electricity that can deposit 108 g of Ag from AgNO₃ solution is:

• a) 1 F
• b) 1 C
• c) 2 A
• d) 1 A

Answer: 1 F

Question: To deposit one equivalent weight of silver at cathode, the charge required will be

• a)  9.65 × 10⁴ C
• b)  9.65 × 10⁵ C
• c) 9.65 × 10³ C
• d) 9.65 × 10⁷ C

Answer: 9.65 × 10⁴ C

Question: The volume of oxygen gas liberated at NTP by passing a current of 9650 coulombs through acidified water is

• a) 2.24 litre
• b) 22.4 litre
• c) 1.12 litre
• d) 11.2 litre

Answer: 2.24 litre

Question:  Three faradays electricity was passed through an aqueous solution of iron (II) bromide. The weight of iron metal (at. wt = 65) deposited at the cathode (in gm) is

• a) 84
• b) 168
• c) 56
• d) 112

Answer: 84

Question: On passing C ampere of electricity through a electrolyte solution for t second. m gram metal deposits on cathode. The equivalent weight E of the metal is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The number of electrons passing per second through a cross-section of copper wire carrying 10^–6 amperes of current per second is found to be

• a) 6 × 10¹²
• b) 6 × 10^–35
• c) 1.6 × 10^–19
• d) 6 × 10^–16

Answer: 6 × 10¹²

Question: Faraday’s laws of electrolysis will fail when

• a) None of these cases
• b) a mixture of electrolytes is used
• c) inert electrodes are used
• d) temperature is increased

Answer: None of these cases

Question: The electric charge for electrode decomposition of one gram equivalent of a substance is

• a) charge on one mole of electrons
• b) one ampere for one hour
• c) 96500 coulombs per second
• d) one ampere per second

Answer: charge on one mole of electrons