NEET AIPMT Chemistry Chapter Wise Solutions – Electrochemistry

NEET AIPMT Chemistry Chapter Wise Solutions – Electrochemistry

NEET AIPMT Chemistry Chapter Wise SolutionsPhysicsBiology

1. In the electrochemical cell : Zn|ZnSO₄(0.01 M)| |CuS0₄( 1.0 M)|Cu, the emf of this Daniell cell is E₁ When the concentration of ZnS0₄ is changed to 1.0 M and that of CuS0₄ changed to 0.01 M, the emf changes to E₂ From the followings, which one is the relationship between E₁ and E₂  ?(Given, RT/F = 0.059) (MEET 2017)
(a) E₁<E₂
(b)E₁>E₂
(c) E₂ = 0¹E₁
(d) E₁=E₂²

2. The molar conductivity of a 0.5 mol/dm³ solution of AgN0₃ with electrolytic conductivity of 5.76 x 10^-3 S cm^-1 at 298 K is (NEET-II 2016)
(a) 2.88 S cm²/mol
(b) 11.52 S cm²/mol
(c) 0.086 S cm²/mol
(d) 28.8 S cm²/mol

3. During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is(NEET-II 2016)
(a) 55 minutes
(b) 110 minutes
(c) 220 minutes
(d) 330 minutes.

4. If the E°_cell for a given reaction has a negative value, which of the following gives the correct relationships for the values of AG° and K ? (NEET-II 2016, 2011)
(a) ΔG° > 0; K_eq < 1
(b) ΔG° > 0; K_eq > 1
(c) ΔG° < 0; K_eq > 1
(d) ΔG° < 0; K_eq < 1

5. The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is (charge on electron = 1.60 x 10^-19 C) (NEET-II 2016)
(a) 6 x 10²³
(b) 6 x 10²⁰
(c) 3.75 x 10²⁰
(d) 7.48 x 10²³

6. Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because (NEET-II2016)
(a) zinc is lighter than iron
(b) zinc has lower melting point than iron
(c) zinc has lower negative electrode potential than iron 1
(d) zinc has higher negative electrode potential than iron.

7.The pressure of H₂ required to make the potential of H₂-electrode zero in pure water at 298 K is (NEET-I 2016)
(a) 10^-10 atm
(b) 10^-4 atm
(c) 10^-14 atm
(d) 10^-12 atm

8. A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as (2015, Cancelled)
(a) dynamo
(b) Ni-Cdcell
(c) iuel cell
(d) electrolytic cell.

9. When 0.1 mol MnO₄^2- is oxidised the quantity of electricity required to completely oxidise MnO₄^2- to Mn0₄^–is (2014)
(a) 96500 C
(b) 2 x 96500 C
(c) 9650C
(d) 96.50 C

10. The weight of silver (at. wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of 0₂ at STP will be (2014)
(a) 5.4 g
(b) 10.8 g
(c) 54.0 g
(d) 108.0 g

11. At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^-1 cm² mol^-1  and at infinite dilution its molar conductance is 238 ohm^-1 cm² mol^-1 . The degree of ionisation of ammonium hydroxide at the same concentration and temperature is (NEET 2013)
(a) 4.008%
(b) 40.800%
(c) 2.080%
(d) 20.800%

12. A button cell used in watches function as following. 

The cell potential will be (NEET 2013)
(a) 0.84 V
(b) 1.34 V
(c) 1.10V
(d) 0.42V

13. A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be (NEET 2013)
(a) 0.118V
(b) 1.18V
(c) 0.059 V
(d) 0.59 V

14. Consider the half-cell reduction reaction
Mn²⁺ + 2e^– —> Mn , E° = – 1.18 V
Mn²⁺ Mn³⁺ + e^– , E° = – 1.51 V
The E° for the reaction 3Mn²⁺ —> Mn° + 2Mn³⁺,
and possibility of the forward reaction are
respectively (Karnataka NEET 2013)
(a) – 4.18 V and yes
(b) + 0.33 V and yes
(c) + 2.69 V and no
(d) – 2.69 V and no

15. How many gram of cobalt metal will be deposited when a solution of cobalt(II) chloride is electrolyzed with a current of 10 amperes for 109 minutes (1 Faraday = 96,500 C; Atomic mass of Co = 59 u) (Karnataka NEET 2013)
(a) 4.0
(b) 20.0
(c) 40.0
(d) 0.66

16. Limiting molar conductivity of NH₄OH [i.e. ∧°_m(NH₄OH)] is equal to

17. Standard reduction potentials of the half reactions are given below :

The strongest oxidising and reducing agents 23 respectively are (Mains 2012)
(a) F₂ and I^–
(b) Br₂ and Cl^–
(c) Cl₂ and Br^–
(d) Cl₂ and I₂

18. Molar conductivities (Λ°_m) at infinite dilution of NaCl, HCl and CH₃COONa are 126.4 ,425.9 and 91.0 S cm² mol^-1 respectively. (Λ°_m) for CH₃COOH will be (Mains 2012)
(a) 425.5 S cm² moL^-1
(b) 180.5 S cm² moL^-1
(c) 290.8 S cm² moL^-1
(d) 390.5 S cm² mol^-1

19. The Gibb’s energy for the decomposition of Al₂0₃ at 500°C is as follows
2/3 Al₂0₃ —> 4/3 Al + O₂
Δ_rG = + 960 kJ mol^-1
The potential difference needed for the electrolytic reduction of aluminium oxide (Al₂0₃) at 500°C is at least (Mains 2012)
(a) 4.5 V
(b) 3.0 V
(c) 2.5 V
(d) 5.0 V

20. 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 (2011)
(a) Y> Z> X
(b) Y> X> Z
(c) Z>X> Y
(d) X> Y> Z

21. The electrode potentials for Cu²⁺_(aq)+ e^– —> Cu⁺_(aq) and Cu⁺_(aq) + e^– —> Cu_(s) are + 0.15 V and + 0.50 V respectively. The value of E°Cu²⁺/Ca will be (2011)
(a) 0.500 V
(b) 0.325 V
(c) 0.650 V
(d) 0.150 V

22. 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 (2011)
(a) + 1.19 V
(b) + 0.89 V
(c) +0.18 V
(d) + 1.83 V

23. A solution contains Fe²⁺, Fe³⁺ and I ^– ions. This solution was treated with iodine at 35 °C. E° for Fe³⁺/Fe²⁺ is + 0.77 V and E° for I₂/2I ^– = 0.536 V. The favourable redox reaction is (Mains 2011)
(a) I₂ will be reduced to I ^–
(b) there will be no redox reaction
(c) I ^– will be oxidised to I₂
(d) Fe²⁺ will be oxidised to Fe³⁺

24. For the reduction of silver ions with copper metal, the standard cell potential was found to be + 0.46 V at 25 °C. The value of standard Gibb’s energy, ΔG° will be (2010)
(F = 96500 C mol^-1)
(a) – 89.0 kJ
(b) – 89.0 J
(c) – 44.5 kJ
(d) – 98.0 kJ

25. An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to (2010)
(a) increase in ionic mobility of ions
(b) 100% ionisation of electrolyte at normal dilution
(c) increase in both i.e., number of ions and ionic mobility of ions
(d) increase in number of ions.

26. Which of the following expressions correctly represents the equivalent conductance at infinite dilution of Al₂(S0₄)₃. Given that Λ° _Al3+ and Λ° _{So4^{2 –}} are the equivalent conductances at infinite dilution of the respective ions? (Mains 2010)

27. Consider the following relations for emf of an electrochemical cell
(i) EMF of cell = (Oxidation potential of anode)
– (Reduction potential of cathode)
(ii) EMF of cell = (Oxidation potential of anode)
+ (Reduction potential of cathode)
(iii) EMF of cell = (Reductional potential of j anode) + (Reduction potential of cathode) j
(iv) EMF of cell = (Oxidation potential of anode)
– (Oxidation potential of cathode)
Which of the above relations are correct? (Mains 2010)
(a) (iii) and (i)
(b) (i) and (ii)
(c) (iii) and (iv)
(d) (ii) and (iv)

28. Given : (2009)

(a) 0.90 V
(b) 0.30 V
(c) 0.38 V
(d) 0.52 V

29. Al₂0₃ is reduced by electrolysis at low potentials and high currents. If 4.0 x 10⁴ amperes of current is passed through molten Al₂0₃ for 6 hours, what mass of aluminium is produced? (Assume 100% current efficiency, at. mass of Al = 27 g mol^-1). (2009)
(a) 8.1 x 10⁴ g
(b) 2.4 x 10⁵ g
(c) 1.3 x 10⁴ g
(d) 9.0 x 10³ g

30. The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mho cm² and at infinite dilution is 400 mho cm². The dissociation constant of this acid is (2009)
(a) 1.25 x 10^-6
(b) 6.25 x 10^-4
(c) 1.25 x 10^-4
(d) 1.25 x 10^-5

31. On the basis of the following E° values, the strongest oxidizing agent is  (2008)

(a) Fe³⁺
(b) [Fe(CN)₆]^3-
(c) [Fe(CN)₆]^4-
(d) Fe²⁺

32. Kohlrausch’s law states that at (2008)
(a) Infinite dilution, each ion makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte
(b) Infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte
(c) Finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte
(d) Infinite dilution each ion makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte.

33. Standard free energies of formation (in kJ/mol)at 298 K are -237.2, -394.4 and -8.2 for H₂O_(l), C0_2(g) and pentane (g) respectively. The value of E°cell for the pentane-oxygen fuel cell is (2008)
(a) 1.0968 V
(b) 0.0968V
(c) 1.968 V
(d) 2.0968 V

34. The equilibrium constant of the reaction:
Cu_(s)+ 2Ag_(aq)⁺—> Cu²⁺_(aq)+ 2Ag_(S);
E° = 0.46 V at 298 K is (2007)
(a) 2.0 x 10¹⁰
(b) 4.0 x 10¹⁰
(c) 4.0 x 10¹⁵
(d) 2.4 x 10¹⁰

35. The efficiency of a fuel cell is given by (2007)
(a) ΔG/ΔS
(b) ΔG/ΔH
(c) ΔS/ΔG
(d) ΔH/ΔG

36. A hypothetical electrochemical cell is shown below.
A Ι A⁺(x M)II B (y M) I B
The emf measured is + 0.20 V. The cell reaction is (2006)
(a) A + B⁺ —> A⁺ + B
(b) A⁺ + B—>A + B⁺
(c) A⁺ + e^– —> A; B⁺ + e^– —> B
(d) the cell reaction cannot be predicted.

37. (2006)

(a) 0.11 IV
(b) 0.330 V
(c) 1.653 V
(d) 1.212 V

38. 4.5 g of aluminium (at. mass 27 amu) is deposited at cathode from Al3+ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H+ ions in solution by the same quantity of electric charge will be (2005)
(a) 44.8 L
(b) 22.4 L
(c) 11.2L
(d) 5.6 L

39. The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process, is (Atomic mass : A1 = 27) (2005)
(a) 270 kg
(b) 540 kg
(c) 90 kg
(d) 180 kg.

40. 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 = 8.314 J K^-1 mol^-1) (2004)
(a) 2.0 x 10¹¹
(b) 4.0 x 10¹²
(c) 1.0 x 10²
(d) 1.0 x 10¹⁰

41. The e.m.f. of a Daniell cell at 298 K is E1.

When the concentration of ZnS0₄ is 1.0 M and that of CuS0₄ is 0.01 M, the e.m.f. changed to E2. What is the relationship between E1 and E2 ? (2003)
(a) E1 > E2
(b) E1 < E2
(c) E1 = E2
(d) E2 = 0≠E1

42.On the basis of the information available from the reaction,

(2003)
(a) 2.14 V
(b) 428 V
(c) 6.42 V
(d) 8.56 V

43.In electrolysis of NaCl when Pt electrode is taken then H₂ is liberated at cathode while with Hg cathode it forms sodium amalgam  (2002)
(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) Cone, of H+ ions is larger when Pt electrode is taken.

44.Standard electrode potentials are Fe²⁺/Fe;
E° = -0.44 and Fe³⁺/Fe²⁺; E° = 0.77 Fe²⁺ , Fe³⁺ and Fe blocks are kept together, then (2001)
(a) Fe³⁺ increases
(b) Fe³⁺ decreases
(c) Fe²⁺/Fe³⁺ remains unchanged
(d)Fe²⁺ decreases.

45.Equivalent conductances of Ba²⁺ and Cl ^– ions are 127 and 76 ohm^-1 cm^-1 eq^-1 respectively. Equivalent conductance of BaCl₂ at infinite dilution is (2000)
(a) 139.5
(b) 101.5
(c) 203
(d) 279

46.For the disproportionation of copper 2Cu⁺—> Cu²⁺ + Cu, E° is (Given E° for Cu²⁺/Cu is 0.34 V and E° for Cu²⁺/Cu⁺ is 0.15 V.)  (2000)
(a) 0.49 V
(b) -0.19 V
(c) 0.38 V
(d) -0.38 V

47.The specific conductance of a 0.1 N KCl solution at 23°C is 0.012 ohm^-1 cm^-1. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be (1999)
(a) 0.918 cm^-1
(b) 0.66 cm^-1
(c) 1.142 cm^-1
(d) 1.12 cm^-1

48.For the cell reaction,

(1998)
(a) In (C2)
(b) In (C2/C1)
(c) In (C1)
(d) In (C1 + C2)

49. 1997

(a)10⁺¹⁸
(b)10⁺¹⁷
(c)10^-28
(d)10^-27

50. The molar conductances of NaCl, HCl and CH₃COONa at infinite dilution are 126.45,426.16 and 91 ohm^-1 cm² mol^-1 respectively. The molar conductance of CH3COOH at infinite dilution (Λ_{m ∞}) is (1997)
(a) 698.28 ohm^-1 cm² mol^-1
(b) 540.48 ohm^-1 cm² mol^-1
(c) 201.28 ohm^-1 cm² mol^-1
(d) 390.71 ohm^-1 cm² mol^-1

51. A 5 ampere current is passed through a solution of zinc sulphate for 40 minutes. The amount of zinc deposited at the cathode is  (1996)
(a) 0.4065 g
(b) 65.04 g
(c) 40.65 g
(d) 4.065 g

52. Reduction potential for the following half-cell reactions are (1996)

(a) – 0.32 V
(b) + 1.20 V
(c) -1.20 V
(d) + 0.32 V

53. (1995)

(a) acids used in two compartments are different
(b) e.m.f. depends on molarities of acids used
(c) the temperature is constant
(d) pH of 0.1 M HCl and 0.1 M CH₃COOH is not same.

54. On heating one end of a piece of a metal, the other end becomes hot because of (1995)
(a) energised electrons moving to the other end
(b) minor perturbation in the energy of atoms
(c) resistance of the metal
(d) mobility of atoms in the metal.

55.  (1994)

(a) Ba2+
(b) Mg2+
(c) Na+
(d) Li+

56. On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be (1992)
(a) hydrogen
(b) oxygen
(c) hydrogen sulphide
(d) sulphur dioxide.

Answer Key

Explanations