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: A

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: A

Question. Electrolysis of fused NaCl will give
(a) Na
(b) NaClO
(c) NaOH
(d) None of these

Answer: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

Question. Which of the following metals is not produced by electrochemical reduction?
(a) Fe
(b) Mg
(c) Al
(d) Na

Answer: A

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: A

Question. Which colourless gas evolves, when NH₄Cl reacts with zinc in a dry cell battery
(a) H₂
(b) NH₄
(c) N₂
(d) Cl₂

Answer: A

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: A

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: A

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: A

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: A

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: A

Question. Prevention of corrosion of iron by zinc coating is called
(a) galvanization
(b) photoelectrolysis
(c) electrolysis
(d) cathodic protection

Answer: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: C

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: A

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: A

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: A

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: A

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

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A