JEE Chemistry Electrochemistry MCQs Set B

Question: In electrolysis of dilute H₂SO₄ using platinum electrodes

• a) H₂ is evolved at cathode
• b) NH₂ is produced at anode
• c) Cl₂ is obtained at cathode
• d) O₂ is produced

Answer: H₂ is evolved at cathode

Question: In electrolysis of NaCl when Pt electrode is taken then H₂ is liberated at cathode while with Hg cathode it forms sodium amalgam. This is because

• a) more voltage is required to reduce H⁺ at Hg than at Pt
• b) Hg is more inert than Pt
• c) Na is dissolved in Hg while it does not dissolve in Pt
• d) conc. of H⁺ ions is larger when Pt electrode is taken

Answer: more voltage is required to reduce H⁺ at Hg than at Pt

Question: Electrolysis of fused NaCl will give

• a) Na
• b) NaClO
• c) NaOH
• d) None of these

Answer: Na

Question: How many moles of Pt may be deposited on the cathode when 0.80 F of electricity is passed through a 1.0 M solution of Pt⁴⁺?

• a) 0.20 mol
• b) 0.80 mol
• c) 1.0 mol
• d) 0.40 mol

Answer: 0.20 mol

Question: A current strength of 9.65 amperes is passed through excess fused AlCl₃ for 5 hours. How many litres of chlorine will be liberated at STP? (F = 96500 C)

• a) 20.16
• b) 1.008
• c) 2.016
• d) 11.2

Answer: 20.16

Question: A solution of copper sulphate (CuSO₄) is electrolysed for 10 minutes with a current of 1.5 amperes. The mass of copper deposited at the cathode (at. mass of Cu = 63u) is

• a) 0.2938g
• b) 0.3928g
• c) 0.3892g
• d) 0.2398g

Answer: 0.2938g

Question:

• a) 9650 C
• b) 96500 C
• c) 2 × 96500 C
• d) 96.50 C

Answer: 9650 C

Question: The weight of silver (at wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of O₂ at STP will be

• a) 108.0 g
• b) 10.8 g
• c) 5.4 g
• d) 54.9 g

Answer: 108.0 g

Question: Electrolysis of a salt solution was carried out, after some time solution turned yellow than salt can be

(i) NaCl   (ii) KCl
(iii) RbCl (iv) KBr

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

Answer: (i), (ii) and (iii)

Question: Which of the following statements is incorrect?

• a) Both electronic and electrolytic conductance varies similarly with temperature
• b) Both electronic and electrolytic conductance depends on the nature of conducting material
• c) Electronic conductance is independent but electrolytic conductance depends on the amount of the conducting substance
• d) All the above statements are incorrect

Answer:  Both electronic and electrolytic conductance varies similarly with temperature

Question: Which of the following statements is incorrect?

• a) Electrodes made up of gold participates in the chemical reaction.
• b) Electrolytic products of NaCl are Na and Cl₂ whereas of aqueous NaCl are NaOH, Cl₂ and H₂.
• c) Both
• d) None of these

Answer: Electrodes made up of gold participates in the chemical reaction.

Question: During electrolysis of sulphuric acid, which of the following processes is possible at anode?

Choose the correct option based on following statements.
(i) Process A is preferred at higher concentration of sulphuric acid.
(ii) Process B is preferred at higher concentration of sulphuric acid.
(iii) Process A is preferred for dilute sulphuric acid.
(iv) Process B is preferred for dilute sulphuric acid.
(v) Both A and B are equally possible at higher concentration.

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

Answer: (iii) and (ii)

Question: Which of the following metals is not produced by electrochemical reduction?

• a) Fe
• b) Mg
• c) Al
• d) Na

Answer: Fe

Question: As lead storage battery is charged

• a) sulphuric acid is regenerated
• b) lead electrode becomes coated with lead sulphate
• c) the concentration of sulphuric acid decreases
• d) lead dioxide dissolves

Answer: sulphuric acid is regenerated

Question: During the charging of lead storage battery, the reaction at anode is represented by

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Which colourless gas evolves, when NH₄Cl reacts with zinc in a dry cell battery

• a) H₂
• b) NH₄
• c) N₂
• d) Cl₂

Answer: H₂

Question: In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

• a) create potential difference between two electrodes
• b) produce high purity water
• c) generate heat
• d) remove adsorbed oxygen from elctrode surfaces

Answer: create potential difference between two electrodes

Question: Among the following cells:

Leclanche cell (i)
Nickel-Cadmium cell (ii)
Lead storage battery (iii)
Mercury cell (iv)
primary cells are

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

Answer: (i) and (iv)

Question: The electrolyte used in Leclanche cell is

• a) moist paste of NH₄Cl and ZnCl₂
• b) moist sodium hydroxide
• c) paste of KOH and ZnO
• d) 38% solution of H₂SO₄

Answer: moist paste of NH₄Cl and ZnCl₂

Question: A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as

• a) Fuel Cell
• b) Dynamo
• c) Electrolytic cell
• d) Ni-Cd cell

Answer: Fuel Cell

Question: Hydrogen-Oxygen fuel cells are used in space craft to supply

• a) power for pressure
• b) oxygen
• c) water
• d) power for heat and light

Answer: power for pressure

Question: Prevention of corrosion of iron by zinc coating is called

• a) galvanization
• b) photoelectrolysis
• c) electrolysis
• d) cathodic protection

Answer: galvanization

Question: The best way to prevent rusting of iron is

• a) making it cathode
• b) putting in saline water
• c) None of these
• d) Both of these

Answer: making it cathode

Question:  Several blocks of magnesium are fixed to the bottom of a ship to

• a) prevent action of water and salt
• b) make the ship lighter
• c) prevent puncturing by under-sea rocks
• d) keep away the sharks

Answer: prevent action of water and salt

Question: Which of the following batteries cannot be reused?

• a) Mercury cell
• b) Ni-Cd cell
• c) Lead storage battery
• d) None of these

Answer: Mercury cell

Question: Which of the following is a merit of Ni–Cd cell over lead storage battery?

• a) Ni–Cd cell has comparatively longer life
• b) Ni–Cd cell is comparatively economical to manufacture
• c) Ni–Cd cell can be re-used
• d) All the above are the merits of Ni–Cd cell over lead storage battery

Answer: Ni–Cd cell has comparatively longer life

Question: Which of the following statements regarding fuel cell is incorrect?

• a) Fuel cells produce electricity with an efficiency of about 100%.
• b) H₂ – O₂ fuel cell is used in Apollo space programme
• c) These cells are eco-friendly
• d) None of these

Answer: Fuel cells produce electricity with an efficiency of about 100%.

Question: Which one of the following cells can convert chemical energy of H₂ and O₂ directly into electrical energy?

• a) Fuel cell
• b) Mercury cell
• c) Daniell cell
• d) Lead storage cell

Answer: Fuel cell

Question:

(i) Figure 1 represents electrochemical and Figure 3 represents electrolytic cell.
(ii) Figure 2 represents electrolytic and Figure 3 represents electrochemical cell.
(iii) Figure 2 represents a cell which is not working i.e. no current flows through the cell.
(iv) Energy conversion shown in Figure 1 is chemical to electrical whereas energy conversion shown in Figure 2 is electrical to chemical.
Which of the following is the correct coding for the statements above.

• a) TFTT
• b) TTTT
• c) FTFF
• d) TFFT

Answer:  TFTT

Question:

• a) (i) and (iii)
• b) Only (ii)
• c) (i) and (ii)
• d) Only (i)

Answer: (i) and (iii)

Question:  Which of the following is/are correct statement(s) for the addition of Li, K, Rb to the aqueous solution of Na⁺.

(i) The correct order of metals in which they reduce the Na⁺ ion is Rb < K < Li.
(ii) Reduction of metal ions would not take place.

• a) Statement (ii) is correct only
• b) Neither (i) nor (ii) is correct
• c) Statement (i) is correct only
• d) Statement (i) and (ii) are correct

Answer: Statement (ii) is correct only

Question:

Which of the following is the correct coding for the statements above.

• a) TTTTT
• b) FFTTT
• c) TTFTF
• d) FFFTT

Answer: TTTTT

Question:

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

Answer: (i) and (ii)

Question:

• a) TFT
• b) TTT
• c) FFT
• d) FTF

Answer: TFT

Question:

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

Answer: (i) and (ii)

Question:

• a) (A) – (r), (B) – (p), (C) – (q)
• b) (A) – (q), (B) – (p), (C) – (r)
• c) (A) – (p), (B) – (r), (C) – (q)
• d) (A) – (r), (B) – (q), (C) – (p)

Answer: (A) – (r), (B) – (p), (C) – (q)

Question:

• a) (A) – (r), (B) – (p), (C) – (s), (D) – (q)
• b) (A) – (p), (B) – (r), (C) – (s), (D) – (q)
• c) (A) – (q), (B) – (p), (C) – (s), (D) – (r)
• d) (A) – (r), (B) – (s), (C) – (p), (D) – (q)

Answer: (A) – (r), (B) – (p), (C) – (s), (D) – (q)

Question:

• a) (A) – (s), (B) – (p), (C) – (q), (D) – (r)
• b) (A) – (p), (B) – (s), (C) – (q), (D) – (r)
• c) (A) – (s), (B) – (q), (C) – (p), (D) – (r)
• d) (A) – (s), (B) – (p), (C) – (r), (D) – (q)

Answer: (A) – (s), (B) – (p), (C) – (q), (D) – (r)

Question:

• a) (A) – (s), (B) – (r), (C) – (q), (D) – (p)
• b) (A) – (r), (B) – (s), (C) – (q), (D) – (p)
• c) (A) – (s), (B) – (q), (C) – (r), (D) – (p)
• d) (A) – (p), (B) – (r), (C) – (q), (D) – (s)

Answer: (A) – (s), (B) – (r), (C) – (q), (D) – (p)

Question:

• a) (A) – (q), (B) – (r), (C) – (p), (D) – (s)
• b) (A) – (r), (B) – (q), (C) – (p), (D) – (s)
• c) (A) – (q), (B) – (r), (C) – (p), D) – (s)
• d) (A) – (q), (B) – (r), (C) – (s), (D) – (p)

Answer:  (A) – (q), (B) – (r), (C) – (p), (D) – (s)

Question:

• a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• b) Assertion is correct, reason is incorrect
• c) Assertion is incorrect, reason is correct
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is correct, reason is correct; reason is not a correct explanation for assertion

Question: 

Assertion : On increasing dilution, the specific conductance keep on increasing.
Reason : On increasing dilution, degree of ionisation of weak electrolyte increases and molality of ions also increases.

• a) Assertion is incorrect, reason is correct
• b) Assertion is correct, reason is incorrect
• c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: Assertion is incorrect, reason is correct

Question:

Assertion : Galvanised iron does not rust.
Reason : Zinc has a more negative electrode potential than iron.

• a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
• b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
• c) Assertion is correct, reason is incorrect
• d) Assertion is incorrect, reason is correct

Answer: Assertion is correct, reason is correct; reason is a correct explanation for assertion

Question: If salt bridge is removed from two half-cells the voltage

• a) drops to zero
• b) increases gradually
• c) does not change
• d) increases rapidly

Answer: drops to zero

Question: In the electrolytic cell, flow of electrons is from

• a) anode to cathode through internal supply
• b) cathode to anode through internal supply
• c) cathode to anode through external supply
• d) cathode to anode in solution

Answer: anode to cathode through internal supply

Question:

• a) Sn²⁺ is a stronger reducing agent than Hg₂ ²⁺
• b) Sn⁴⁺ is a stronger oxidising agent than Pb⁴⁺
• c) Pb²⁺ is a stronger reducing agent than Sn²⁺
• d) None of these

Answer:  Sn²⁺ is a stronger reducing agent than Hg₂ ²⁺

Question:

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

Answer: (ii) and (iv)

Question:

• a) Mn > Cr > Fe > Co
• b) Fe > Mn > Cr > Co
• c) Cr < Fe > Mn > Co
• d) Cr > Mn > Fe > Co

Answer: Mn > Cr > Fe > Co

Question:

If the standard reduction potential of Cu²⁺/Cu is +0.34 V, the reduction potentials in volts of the above electrodes follow the order.

• a) Q > R > S > P
• b) S > R > Q > P
• c) P > S > R > Q
• d) R > S > Q > P

Answer: Q > R > S > P

Question:

• a) 0.40V
• b) 1.23 V
• c) 0.81V
• d) – 0.40 V

Answer: 0.40V

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) +0.38 V
• b) –0.38 V
• c) +0.49 V
• d) –0.19 V

Answer: +0.38 V

Question:

• a) increase the E and shift equilibrium to the right
• b) lower the E and shift equilibrium to the right
• c) lower the E and shift equlibrium to the left
• d) increase the E and shift equilibrium to the left

Answer: increase the E and shift equilibrium to the right

Question: For a cell reaction involving two electron change, the standard EMF of the cell is 0.295 V at 2°C. The equilibrium constant of the reaction at 25°C will be:

• a) 1 × 10¹⁰
• b) 29.5 × 10^–2
• c) 10
• d) 2.95 × 10^–10

Answer: 1 × 10¹⁰

Question:

• a) + 0.3
• b) 0.5
• c) 1.5
• d) – 0.5

Answer: + 0.3

Question:

• a) 10^37.3
• b) antilog (24.08)
• c) 9.65 × 10⁴
• d) 37.3

Answer: 10^37.3

Question:

• a) 0.8221 V
• b) 0.5282 V
• c) 8.221 V
• d) 9.282 V

Answer: 0.8221 V

Question: The oxidation potential of 0.05 M H₂SO₄ is

• a) +1 × 0.0591
• b) –0.01 × 0.0591
• c) –2 × 0.0591
• d) –2.321 × 0.0591

Answer: +1 × 0.0591

Question:

• a) Concentration of all the reacting species should be unity.
• b) Concentration of all the product species should be unity
• c) Concentration of any one of the reacting species should be unity
• d) Concentration of all reacting and product species should be unity

Answer: Concentration of all the reacting species should be unity.

Question: A 0.5 M NaOH solution offers a resistance of 31.6 ohm in a conductivity cell at room temperature. What shall be the approximate molar conductance of this NaOH solution if cell constant of the cell is 0.367 cm^–1.

• a) 23.2 S cm² mole^–1
• b) 5464 S cm² mole^–1
• c) 234 S cm² mole^–1
• d) 4645 S cm² mole^–1

Answer: 23.2 S cm² mole^–1

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 6.25 × 10^–4 S m2 mol^–1
• b) 62.5 S m² mol^–1
• c) 625 × 10^–4 S m2 mol^–1
• d) None of these

Answer: 6.25 × 10^–4 S m2 mol^–1

Question: The limiting molar conductivities of HCl, CH₃COONa and NaCl are respectively 425, 90 and 125 mho cm² mol^–1 at 25°C. The molar conductivity of 0.1 M CH³COOH solutions is 7.8 mho cm² mol^–1 at the same temperature. The degree of dissociation of 0.1 M acetic acid solution at the same temperature is

• a) 0.02
• b) 0.03
• c) 0.10
• d) 0.15

Answer: 0.02

Question: A weak electrolyte having the limiting equivalent conductance of 400 S cm². equivalent^–1 at 298 K is 2% ionized in its 0.1 N solution. The resistance of this solution (in ohms) in an electrolytic cell of cell constant 0.4 cm^–1 at this temperature is

• a) 500
• b) 300
• c) 200
• d) 400

Answer: 500

Question:

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

Answer: (i) and (ii)

Question: Arrange the following in increasing order of their conductivity Na⁺ (A), K⁺ (B), Ca²⁺ (C), Mg²⁺(D)

• a) A, B, D, C
• b) B, A, C, D
• c) A, B, C, D
• d) C, A, D, B

Answer: A, B, D, C

Question: The conductivity of electrolytic solutions depends upon which of the following?

(i) Size of ions produced
(ii) Viscosity of the solvent
(iii) Concentration of electrolyte
(iv) Solvation of ions produced

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

Answer: All of these

Question:  Mark the false statement?

• a)

  

• b) The efficiency of a hydrogen-oxygen fuel cell is 23%
• c) A salt bridge is used to eliminate liquid junction potential
• d) None of these

Answer:

Question: When electric current is passed through acidified water, 112 ml of hydrogen gas at STP collected at the cathode in 965 seconds. The current passed in amperes is

• a) 1.0
• b) 0.1
• c) 2.0
• d) 0.5

Answer: 1.0

Question: On passing current through two cells, connected in series containing solution of AgNO₃ and CuSO₄, 0.18 g of Ag is deposited. The amount of the Cu deposited is:

• a) 0.0529 g
• b) 0.529 g
• c) 10.623 g
• d) 1.2708 g

Answer: 0.0529 g

Question: In the electrolysis of water, one faraday of electrical energy would liberate

• a) 8 g oxygen
• b) one mole of oxygen
• c) one gram atom of oxygen
• d) 22.4 lit. of oxygen

Answer: 8 g oxygen

Question:  Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of H₂ gas at the cathode is (1 Faraday = 96500 C mol^–1)

• a) 19.3 × 10⁴ sec
• b) 38.6 × 10⁴ sec
• c) 9.65 × 10⁴ sec
• d) 28.95 × 10⁴ sec

Answer: 19.3 × 10⁴ sec

Question: What is the amount of chlorine evolved when 2 amperes of current is passed for 30 minutes in an aqueous solution of NaCl ?

• a) 1.32 g
• b) 99 g
• c) 66 g
• d) 33 g

Answer: 1.32 g

Question: On passing a current of 1.0 ampere for 16 min and 5 sec through one litre solution of CuCl₂, all copper of the solution was deposited at cathode. The strength of CuCl₂ solution was (Molar mass of Cu= 63.5; Faraday constant = 96,500 Cmol^–1)

• a) 0.01 N
• b) 0.02 M
• c) 0.01 M
• d) 0.2 N

Answer:  0.01 N

Question: 0.2964 g of copper was deposited on passage of a current of 0.5 amp for 30 mins through a solution of copper sulphate. Calculate the oxidation state of Cu (At. mass 63.56).

• a) +2
• b) +4
• c) +1
• d) +3

Answer: +2

Question: One Faraday of electricity is passed through molten Al₂O₃, aqueous solution of CuSO₄ and molten NaCl taken in three different electrolytic cells connected in series. The mole ratio of Al, Cu and Na deposited at the respective cathode is

• a) 2 : 3 : 6
• b) 6 : 3 : 2
• c) 6 : 2 : 3
• d) 1 : 2 : 3

Answer: 2 : 3 : 6

Question:  What will happen during the electrolysis of aqueous solution of CuSO₄ by using platinum electrodes ?

(i) Copper will deposit at cathode.
(ii) Copper will deposit at anode.
(iii) Oxygen will be released at anode.
(iv) Copper will dissolve at anode.

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

Answer: (i) and (iii)

Question:

• a) 3F
• b) 2F
• c) 6F
• d) 1F

Answer: 3F

Question: When a lead storage battery is discharged

• a) Sulphuric acid is consumed
• b) Lead is formed
• c) Lead sulphate is consumed
• d) SO₂ is evolved

Answer:  Sulphuric acid is consumed

Question: The most durable metal plating on iron to protect against corrosion is

• a) zinc plating
• b) copper plating
• c) nickel plating
• d) tin plating

Answer: zinc plating