Electrochemistry MCQ Class 12 Chemistry
Please refer to Chapter 3 Electrochemistry MCQ Class 12 Chemistry with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Chemistry. Students should refer to MCQ Questions for Class 12 Chemistry with Answers to score more marks in Grade 12 Chemistry exams. Students should read the chapter Electrochemistry and then attempt the following objective questions.
MCQ Questions Class 12 Chemistry Chapter 3 Electrochemistry
The Electrochemistry MCQ Class 12 Chemistry provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.
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
Question. Which device converts chemical energy of a spontaneous redox reaction into electrical energy?
(a) Galvanic cell
(b) Electrolytic cell
(c) Daniell cell
(d) Both (a) and (c)
Question. The tendency of an electrode to lose electrons is known as
(a) electrode potential
(b) reduction potential
(c) oxidation potential
Question. The reference electrode is made by using
Question. Which of the following statements is incorrect regarding electrochemistry?
(a) It is the study of production of electricity from energy released during spontaneous chemical reactions.
(b) NaOH, Cl2, alkali and alkaline earth metals are prepared by electrochemical methods.
(c) The demerit associated with electrochemical methods is that they are more polluting. Thus they are ecodestructive.
(d) Electrochemical reactions are more energy efficient and less polluting.
Question. What flows in the internal circuit of a galvanic cell?
Question. In which of the following conditions salt bridge is not required in a galvanic cell?
(a) When galvanic cell is used in geyser.
(b) When distance between oxidation half cell and reduction half cell is negligible.
(c) Electrolytic solutions used in both the half cells are of same concentration.
(d) When both the electrodes are dipped in the same electrolytic solution.
Question. The standard hydrogen electrode potential is zero, because
(a) hydrogen oxidized easily
(b) electrode potential is considered as zero
(c) hydrogen atom has only one electron
(d) hydrogen is a very light element
Question. The oxidation potentials of A and B are +2.37 and +1.66 V respectively. In chemical reactions
(a) A will be replaced by B
(b) A will replace B
(c) A will not replace B
(d) A and B will not replace each other
Question. Without losing its concentration ZnCl2 solution cannot be kept in contact with
Question. Which of the following statement is not correct about an inert electrode in a cell ?
(a) It does not participate in the cell reaction.
(b) It provides surface either for oxidation or for reduction reaction.
(c) It provides surface for conduction of electrons.
(d) It provides surface for redox reaction.
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 × 101
(b) 1.0 × 105
(c) 1.0 × 1010
(d) 1.0 ×1030
Question. A smuggler could not carry gold by depositing iron on the gold surface since
(a) gold is denser
(b) iron rusts
(c) gold has higher reduction potential than iron
(d) gold has lower reduction potential than iron
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
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) 100 ohm–1 cm2
(b) 515 ohm–1 cm2
(c) 630 ohm–1 cm2
(d) 6300 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) 0.142 cm–1
(b) 0.66 cm–1
(c) 0.918 cm–1
(d) 1.12 cm–1
Question. The unit of specific conductivity is
(a) ohm cm–1
(b) ohm cm–2
(c) ohm–1 cm
(d) 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
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) 0.0616 cm–1
(b) 0.66 cm–1
(c) 6.60 cm–1
(d) 660 cm–1
Question. The unit of equivalent conductivity is
(a) ohm cm
(b) ohm–1 cm2 (g equivalent)–1
(c) ohm cm2 (g equivalent)
(d) S cm–2
Question. Which of the following is the use of electrolysis?
(c) Both (a) & (b)
(d) None of these
Question. Which of the following does not conduct electricity?
(a) Fused NaCl
(b) Solid NaCl
(c) Brine solution
Question. The specific conductivity of 0.1 N KCI solution is 0.0129 Ω-1 cm-1 . The resistance of the solution in the cell is 100 Ω. The cell constant of the cell will be
Question. If the molar conductance values of Ca2+ and Cl– at infinite dilution are respectivelyl 18.88 x 10-4 m2 mho mol-1 and 77. 33 x 10-4 m2 rnho mol-1 then that of CaCl2 is(in m2 mho mol-1)
(a) 118.88 X 10-4
(b) 154.66 X 10-4
(c) 273. 54 X 10-4
(d) 196. 21 X 10-4
Question. For strong electrolytes the plot of molar conductance vs ✓C is
Question. The units of equivalent conductance, are
(a) Ω cm2 equiv-1
(b) Ω cm2 equiv
(c) Ω-1 cm2 equiv-1
(d) Ω cm2 equiv
Question. Pure water does not conduct electricity because it is
(b) almost not ionised
(c) decomposed easily
Question. The specific conductance (K) of an electrolyte of 0.1 N concentration is related to equivalent conductance (A) by the following fonnula
(a) A = K
(b) A = 10 K
(c) A = 100K
(d) A = 10000K
Question. The limiting molar conductivities A° for NaCl, KBr and KCl are 126, 152 and l 50 S cm2 mol-1 respectively. The A° for NaBr is
(a) 128 S cm2 mol-1
(b) 176 S cm2 mol-1
(c) 278 S cm2 mol-1
(d) 302 S cm2 mol-1
Question. The equivalent conductivity of a solution containing 2.54g of CuSO4 per L is 91.0∞-1cm2 eq-1. Its conductivity would be
(a) 2.9 x 10-3 Ω-1 cm-1
(b) 1.8 x 10-2 Ω-1 cm-1
(c) 2.4 x 10-4 Ω-1 cm-1
(d) 3.6 x 10-3 Ω-1 cm-1
Question. At 298K the molar conductivities at infinite dilution (A°M) of NH4Cl, KOH and KCI are 152.8, 272.6 and 149.8 S cm2 mol-1 respectively. The A°M of NH4OH is Scm2mol-1 and % dissociation of 0.01 M NH4OH with Am = 25 .15 cm2mol-1 at the same temperature are
(a) 275.6, 091
(b) 275.6, 9.1
(c) 266.6, 9.6
(d) 30, 84
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) 107.88 gm
(b) 1.6 gm
(c) 0.8 gm
(d) 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)
(b) 3.18 g
Question. The cell constant of a conductivity cell ___________.
(a) changes with change of electrolyte.
(b) changes with change of concentration of electrolyte.
(c) changes with temperature of electrolyte.
(d) remains constant for a cell.
Question. On which of the following magnitude of conductivity does not depends?
(a) Nature of material
(d) Mass of the material
Question. A silver cup is plated with silver by passing 965 coulombs of electricity. The amount of Ag deposited is :
(a) 107.89 g
(b) 9.89 g
(c) 1.0002 g
(d) 1.08 g
Question. The number of coulombs required to reduce 12.3 g of nitrobenzene to aniline is :
(a) 115800 C
(b) 5790 C
(c) 28950 C
(d) 57900 C
Question. The amount of electricity that can deposit 108 g of Ag from AgNO3 solution is:
(a) 1 F
(b) 2 A
(c) 1 C
(d) 1 A
Question. Electrolysis of fused NaCl will give
(d) None of these
Question. Which of the following statements is incorrect?
(a) Both electronic and electrolytic conductance depends on the nature of conducting material.
(b) Both electronic and electrolytic conductance varies similarly with temperature.
(c) Electronic conductance is independent but electrolytic conductance depends on the amount of the conducting substance.
(d) All the above statements are incorrect.
Question. Which of the following metals is not produced by electrochemical reduction?
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
Question. As lead storage battery is charged
(a) lead dioxide dissolves
(b) sulphuric acid is regenerated
(c) lead electrode becomes coated with lead sulphate
(d) the concentration of sulphuric acid decreases
Question. Faraday’s laws of electrolysis will fail when
(a) temperature is increased
(b) inert electrodes are used
(c) a mixture of electrolytes is used
(d) None of these cases
Question. The electric charge for electrode decomposition of one gram equivalent of a substance is
(a) one ampere per second
(b) 96500 coulombs per second
(c) one ampere for one hour
(d) charge on one mole of electrons
Question. In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to
(a) produce high purity water
(b) create potential difference between two electrodes
(c) generate heat
(d) remove adsorbed oxygen from elctrode surfaces
Question. Hydrogen-Oxygen fuel cells are used in space craft to supply
(a) power for heat and light
(b) power for pressure
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) Hg is more inert than Pt
(b) more voltage is required to reduce H+ at Hg than at 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
Question. Prevention of corrosion of iron by zinc coating is called
(c) cathodic protection
Question. Which of the following batteries cannot be reused?
(a) Lead storage battery
(b) Ni-Cd cell
(c) Mercury cell (d) Both
(b) and (c)
Question. I. Cu+ 2HCl → CuCl2 + H2 (g)
(E°Cu2+ /Cu = + 0.34 V)
II. Zn + 2HC1 → ZnCl2 + H2 (g)
(E°Zn2+ / Zn=- 0.76 V)
III. Ag + 2HCl → AgCl + 1/2 H2 (g)
(E°Ag2+ / Ag =- 0.76 V)
Which of the following reaction is feasible?
(d) All of these
Question. The electrochemical cell shown below is a concentration cell. M / M2+ (saturated solution of a sparingly soluble salt, MX2 ) 11M2+ (0.00001 mol dm-3 / M). The emf of the cell depends on the difference in concentration of M2+ ions at the two electrodes. The emf of the cell at 298 is 0.059 V.
The value of /ΔG (kJ mol-1 ) for the given cell is (takelF = 96500C mol-1)
(a) – 5.7
(d) – 11.4
Question. At 25°C temperature, the cell potential of a given electrochemical cell is 1.92 V. Find the value ofx.
Mg(s) l Mg2+ (aq) x M ll Fe2+ (aq) 0.01 M l Fe (s)
E° Mg l Mg2+ (aq) = 2.37V;E°Fe/ Fe2+ (aq) = 0.45V
(a) x = 0.01M
(b) x < 0.01 M
(c) x > 0.01 M
(d) x cannot be predicted
Question. The emfofthe cell NilNi2+ ( 1.0 M) ll Au3+ (1.0 M) l Au is [E° (Ni2+/Ni) = – 0.25 Vand
E°( Au3+ / Au ) = + 1.5 V
(a) 2.00 V
(b) 1.25 V
(c) – 1.25 V
(d) 1.75 V
Question. If the standard electrode potential of Cu2+ / Cu electrode is 0.34 V, what is the electrode potential at 0.01 M concentration of Cu2+? (T = 298 K)
(a) 0.399 V
(b) 0.281 V
(c) 0.222 V
(d) 0.176 V
Question. The standard reduction potential for Zn 2 + / Zn, Ni 2+ /Ni and Fe2 + /Fe are – 0.76, – 0.23 and – 0.44 Vrespectively. The reaction X + Y 2 + ➔ X 2 + + Y will be spontaneous when
(a) X = Ni, Y = Fe
(b) X = Ni, Y = Zn
(c) X = Fe, Y = Zn
(d) X = Zn, Y = Ni
Question. E°Fe3+/Fe = – 0.336 V, E°Fe3+/Fe = – 0.439 V. The value of standard electrode potential for the charge, Fe3+(aq)+e–→ Fe2+(aq)willbe
(a) – 0.072 V
(b) 0.385 V
(c) 0.770 V
(d) – 0.270 V
Question. Daniel cell, anode and cathode are, respectively
(a) Zn l Zn2+ and Cu2+ l Cu
(b) Cu l Cu2+ and Zn2+ l Zn
(c) Fe l Fe2+ and Cu2+ l Cu
(d) Cu l Cu2+ and Fe2+ l Fe
Question. The potential of the following cell is 0.34V at 25°C. Calculate the standard reduction potential of the copper half-cell.
Pt l H2 (1 atm) l H+ (1 M) ll Cu2+ (1 M) l Cu
(a) – 3.4 V
(b) + 3.4 V
(c) – 0.34 V
(d) + 0.34 V
Question. The potential of the cell for the reaction,
M(s) + 2H+ (1M) → H2 (g)(1atm) + M2+ (0.1M) is 1.500 V. The standard reduction potential for M2+ I
M (s) couple is
(a) 0.1470 V
(d) None of the above
Question. In which of the following pairs, the constants/ quantities are not mathematically related to each other?
(a) Gibbs free energy and standard cell potential
(b) Equilibrium constant and standard cell potential
(c) Rate constant and activation energy
(d) Rate constant and standard cell potential
Question. Small quantities of solutions of compounds TX, TY and TZ are put into separate test tubes containing X, Y and Z solutions. TX does not react with any of these. TY reacts with both X and Z. 1Z reacts with X. The decreasing order of ease of oxidation of the anions X – , y – , z- is
(a) Y– ,Z– ,X–
(b) Z– ,X– ,Y–
(c) Y– ,X– ,Z–
(d) X– ,Z– ,Y–
Question. Cu+ ( aq) is unstable in solution and undergoes simultaneous oxidation and reduction, according to the reaction 2Cu+ (aq) ⇌ Cu2+ (aq) + Cu(s) choose correct E° for the above reaction, if
E°Cu2+/Cu = 0. 34 V and E°Cu2+/Cu+= 0.15 V
Question. The most durable metal plating on iron to protect against corrosion is
(a) nickel plating
(b) copper plating
(c) tin plating
(d) zinc plating
Question. The best way to prevent rusting of iron is
(a) making it cathode
(b) putting in saline water
(c) Both of these
(d) None of these
Question. Several blocks of magnesium are fixed to the bottom of a ship to
(a) make the ship lighter
(b) prevent action of water and salt
(c) prevent puncturing by under-sea rocks
(d) keep away the sharks
Question. Which of the following statements is incorrect regarding dry (Leclanche) cell?
(a) Cathode used in the cell is coated by powdered manganese dioxide and carbon.
(b) Most common application of this cell is in our transistors and clocks.
(c) At cathode, Mn is oxidised from + 3 to + 4.
(d) At anode Zn is oxidised from 0 to + 2.
Question. If salt bridge is removed from two half-cells the voltage
(a) drops to zero
(b) does not change
(c) increases gradually
(d) increases rapidly
Question. In the electrolytic cell, flow of electrons is from
(a) cathode to anode in solution
(b) cathode to anode through external supply
(c) cathode to anode through internal supply
(d) anode to cathode through internal supply
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) (ii) and (iv)
(c) (i) and (ii)
(d) (ii) and (iii)
Question. Which of the following is a merit of Ni–Cd cell over lead storage battery?
(a) Ni–Cd cell can be re-used.
(b) Ni–Cd cell is comparatively economical to manufacture
(c) Ni–Cd cell has comparatively longer life
(d) All the above are the merits of Ni–Cd cell over lead storage battery.
Question. Which of the following statements regarding fuel cell is incorrect?
(a) These cells are eco-friendly.
(b) These cells convert energy of combustion of fuels like H2, CH4, CH3OH etc., directly into electrical energy.
(c) H2 – O2 fuel cell is used in Apollo space programme.
(d) Fuel cells produce electricity with an efficiency of about 100%.
Question. When a lead storage battery is discharged
(a) SO2 is evolved
(b) Lead sulphate is consumed
(c) Lead is formed
(d) Sulphuric acid is consumed
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