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: A

Question. What flows in the internal circuit of a galvanic cell?
(a) Ions
(b) Electricity
(c) Electrons
(d) Atoms

Answer: A

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: A

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: A

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: A

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: A

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: A

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: A

Question. The reference electrode is made by using
(a) Hg₂Cl₂
(b) CuSO₄
(c) ZnCl₂
(d) None of these

Answer: A

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: A

Question. Without losing its concentration ZnCl₂ solution cannot be kept in contact with
(a) Al
(b) Ag
(c) Au
(d) Pb

Answer: A

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

Answer: A

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

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

Question. Which of the following is the use of electrolysis
(a) Both
(b) Electrorefining
(c) Electroplating
(d) None of these

Answer: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A