ELECTROCHEMISTRY WORKSHEET FOR JEE-ADVANCE/AIIMS 1. 2. 3. 4. 5. 6. 1 The standard electrode potential values of the element A, B and C are 0.68, −2.50 and −0.50 V respectively. The order of their reducing power is : (a) A > B > C (b) A > C >B (c) C > B > A (d) B > C > A The following four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue ? The oxidation potentials of Zn, Ag, Cd, Pb and Cu are +0.76, -0.80, +0.40, +0.13 and −0.34 respectively (a) Zn(NO3)2 (b) AgNO3 (d) Pb(NO3)2 (c) Cd(NO3)2 + For the electrochemical cell, M | M || X | X, E°(M+/M)=0.44 V and E°(X/X ) =0.33V. From this data, one can deduce that (a) M + X → M+ + X is the spontaneous reaction (b) M+ + X → M + X is the spontaneous reaction (c) Ecell = 0.77 V (d) Ecell = −0.77 V The standard electrode potentials of Zn2+/Zn and Ag+/Ag are – 0.763 V and +0.799 V respectively. The standard potential of the cell is… [KCET 1993] (a) 1.56 V (b) 0.036 V (c) –1.562V (d) 0.799 V Which of the following metal does not react with the solution of copper sulphate…? [CPMT 1999] (a) Mg (b) Fe (c) Zn (d) Ag The standard oxidation potential of zinc and silver in water at 298 K are Zn(s) →Zn2+ + 2e– ; E = 0.76 V Ag(s) → Ag+ + e– ; E = – 0.80 V Which of the following reactions actually take place [KCET 2003] + ++ (a) Zn(s) + 2Ag (aq) → Zn (aq) + 2Ag(s) (b) Zn++(aq) + 2Ag(s) → Zn (s) + 2 Ag+(aq) (c) Zn (s) + Ag(s) → Zn++ (aq) + Ag+(aq) (d) Zn++(aq) + Ag+(aq) → Zn (s) + Ag(s) Electrochemistry-Worksheet JEE Advance/AIIMS 7. 8. 9. 10. 11. 12. 13. 14. 2 Consider the reaction Mn+(aq) + ne– → M(s). The standard reduction potential values of the elements M1, M2 and M3 are – 0.34 V, – 3.05 V and –1.66 V respectively. The order of their reducing power will be (a) M1 > M2 > M3 (b) M3 > M2 > M1 (c) M1 > M3 > M2 (d) M2 > M3 > M1 Four alkali metals A, B, C and D are having respectively standard electrode potential as –3.05, –1.66, –0.40 and 0.80. Which one will be the most reactive… [CPMT 1983; MP PET/PMT 1988; MNR 1993; UPSEAT 2002] (a) A (b) B (c) C (d) D Which one of the following reaction is not possible… [MP PMT 1991] (a) Fe + H2SO4 →FeSO4 + H2 (b) Cu + 2AgNO3 →Cu (NO3)2 + 2Ag (c) 2KBr + I2 →2KI + Br2 (d) CuO + H2 →Cu + H2O When a rod of metal A is dipped in an aqueous solution of metal B (concentration of B2+ ion being 1M) at 25 0C, the standard electrode potentials are A2+/A = – 0.76 volts, B2+/B = + 0.34 volts. [KCET 1992] (a) A will gradually dissolve (b) B will deposit on A (c) No reaction will occur (d) Water will decompose into H2 and O2 The reaction Zn2+ + 2e–→Zn has a standard potential of –0.76 V. This means… [KCET 1992] (a) Zn can’t replace hydrogen from acids (b) Zn is a reducing agent (c) Zn is an oxidising agent (d) Zn2+ is a reducing agent For a spontaneous reaction the ∆G, equilibrium constant (K) and E0Cell will be respectively. [AIEEE 2005] (a) –ve, > 1, + ve (b) +ve, > 1, –ve (c) –ve, < 1, – ve (d) –ve, > 1, – ve The reference electrode is made form which of the following… [MP PET/PMT 1988; MP PMT 2002] (a) ZnCl2 (b) CuSO4 (c) Hg2Cl2 (d) HgCl2 The standard reduction potential for Li+ / Li ; Zn2+/ Zn; H+/H2 and Ag+ / Ag is – 3.05, –0.762, 0.00 and +0.80V. Which of the following has highest reducing capacity…? [MP PMT 1992] (a) Ag (b) H2 (c) Zn (d) Li Electrochemistry-Worksheet JEE Advance/AIIMS 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. When electric current is passed through a cell having an electrolyte, the positive ions move towards the cathode and the negative ions towards the anode. If the cathode is pulled out of the solution. [AIIMS 1980] (a) The positive and negative ions will move towards the anode (b) The positive ions will start moving towards the anode, the negative ions will stop moving (c) The negative ions will continue to move towards the anode and the positive ions will stop moving (d) The positive and negative ions will start moving randomly In Cu — Zn cell [BHU 1981] (a) Reduction occurs at the copper cathode (b) Oxidation occurs at the copper cathode (c) Reduction occurs at the anode (d) Chemical energy is converted to light energy For cell reaction, Zn + Cu2+ → Zn2+ + Cu, cell representation is… [BCECE 2005] (a) Zn | Zn2+ ||Cu2+ | Cu (b) Cu | Cu2+ ||Zn2+ | Zn (c) Cu | Zn2+ ||Zn | Cu2+ (d) Cu2+| Zn || Zn2+ |Cu Which one is not called an anode reaction from the following… 1 (a) Cl– → Cl2 + e– (b) Cu →Cu++ + 2e– 2 (c) Hg+ →Hg++ + e– (d) Zn2+ + 2e– → Zn A cell from the following which converts electrical energy into chemical energy (a) Dry cell (b) Electrochemical cell (c) Electrolytic cell (d) None of these 2+ 2+ In the cell Zn | Zn ||Cu | Cu, the negative electrode is… [MP PMT 1995] (a) Cu (b) Cu2+ (c) Zn (d) Zn2+ The standard cell potential of Zn | Zn2+(aq) || Cu2+(aq) |Cu cell is 1.10 V. The maximum work obtained by this cell will… [MP PET 2002] (a) 106.15 kJ (b) –212.30 kJ (c) – 318.45 kJ (d) –424.60kJ Consider the Galvanic cell Zn | ZnSO 4 || CuSO4 |Cu the reaction at cathode is… [AMU 2000] 2+ – (a) Zn +2 e →Zn (b) Cu2+ +2 e– → Cu (c) Cu2+ +Zn → Cu + Zn2+ (d) Zn2+ +Cu → Zn + Cu2+ + +2 The cell reaction Cu + 2Ag →Cu + Ag is best represented by… [AMU 2000] 2+ + (a) Cu(s) |Cu (aq)|| Ag (aq) |Ag(s) (b) Pt |Cu+2|| Ag+(aq) |Ag(s) 2+ (c) Cu | Cu ||Pt | Ag (d) None of the above representations 2+ 2+ Zn( g) |Zn ( aq ) || Cu ( aq ) |Cu( s ) is… [Kerala (Engg.) 2002] (anode ) (a) Weston cell (c) Calomel cell 3 (cathode) (b) Daniel cell (d) Faraday cell (e) Standard cell Electrochemistry-Worksheet JEE Advance/AIIMS 25. Saturated solution of KNO3 is used to make ‘salt-bridge’ because… [IIT Screening 2002] – (a) Velocity of K+ is greater than that of NO3 – (b) Velocity of NO3 is greater than that of K+ – 26. 27. 28. 29. 30. 31. 32. 4 (c) Velocity of K+ and NO3 are nearly the same (d) KNO3 is highly soluble in water In balancing the half reaction S2O32– → S(s) the number of electrons that must be [DPMT 2000] added is… (a) 4 on the left (b) 3 on the right (c) 2 on the left (d) 2 on the right Which one of the following statement is true for a electrochemical cell… [Pb. PMT 1999; KCET 1999] (a) H2 is cathode and Cu is anode (b) H2 is anode and Cu is cathode (c) Reduction occurs at H2 electrode (d) Oxidation occurs at Cu electrode Which of the following statements about galvanic cell is incorrect…? [JIPMER 1997] (a) Anode is positive (b) Oxidation occurs at the electrode with lower reduction potential (c) Cathode is positive (d) Reduction occurs at cathode The position of some metals in the electrochemical series in decreasing electropositive character is given as Mg >Al > Zn > Cu > Ag. What will happen, if a copper spoon is used to stir a solution of aluminium nitrate (a) The spoon will get coated with Al (b) An alloy of Cu and Al is formed (c) The solution becomes blue (d) There is no reaction Which of the following is not used to construct salt bridge…? [MP PET 2003] (a) CH3COOK (b) KCl (c) NH4NO3 (d) KNO3 The hydrogen electrode is dipped in a solution of pH = 3 at 25 °C. The oxidation potential of the cell would be (the value of 2.303RT/F is 0.059 V)… [KCET 1993, 2005] (a) 0.177 V (b) – 0.177 V (c) 0.087 V (d) 0.059 V Beryllium is placed above magnesium in the second group. Beryllium dust, therefore when added to MgCl2 solution will… [CPMT 1977] (a) Have no effect (b) Precipitate Mg metal (c) Precipitate MgO (d) Lead of dissolution of Be metal Electrochemistry-Worksheet JEE Advance/AIIMS 33. 34. 35. 36. The name of equation showing relation between electrode potential (E), standard electrode potential (E0) and concentration of ions in solution is (a) Kohlrausch’s equation (b) Nernst’s equation (c) Ohm’s equation (d) Faraday’s equation The correct representation of Nernst’s equation is 0.0591 (a) EM n+ /M = E0 M n+ / M + log ( M n + ) n 0.0591 (b) EM n+ /M = E0 M n+ / M − log ( M n + ) n n (c) EM n+ /M = E0 M n+ / M + log ( M n + ) 0.0591 (d) None of the above Four alkali metals A, B, C and D are having respectively standard electrode potential as – 3.05, –1.66, – 0.40 and 0.80. Which one will be the most reactive [CPMT 1983; MP PET/PMT 1988; MNR 1993; UPSEAT 2002] (a) A (b) B (c) C (d) D What is the correct Nernst equation for reaction taking place in the following cell [Gujarat CET 2007] 2+ – Mg(s) | Mg (aq) || Cl (aq)|Cl2(g) (1 atm)/Pt 2 (a) Ecell = E 0 cell Cl − 0.0592 − × log n Mg 2 + 2+ (b) Ecell = E 0 cell Mg 0.0592 − × log − n Cl 2 0.0592 × log Mg 2 + Cl − n Mg 2 + 0.0592 0 (d) Ecell = Ecell − × log 2 n Cl − E0 values of Mg2+/ Mg is – 2.37 V, of Zn2+ / Zn is – 0.76V and Fe2+ /Fe is – 0.44V. Which of the following statements is correct…? [EAMCET 1989] (a) Zn will reduce Fe2+ (b) Zn will reduce Mg2+ (c) Mg oxidises Fe (d) Zn oxidises Fe 2+ The standard reduction potential for Fe / Fe and Sn2+ / Sn electrodes are –0.44 and –0.14 volt respectively. For the given cell reaction Fe2+ + Sn →Fe + Sn2+, the standard EMF is [IIT Screening 1990 MP PMT 2003] (a) +0.30 V (b) – 0.58 V (c) +0.58 V (d) –0.30 V 0 0 When EAg+ / Ag = 0.8 volt and EZn2+ /Zn = − 0.76 volt. Which of the following is 0 (c) Ecell = Ecell − 37. 38. 39. correct…? (a) Ag+ can be reduced by H2 (c) Zn2+ can be reduced by H2 5 [MP PMT 1994] (b) Ag can oxidize H2 into H+ (d) Ag can reduce Zn2+ ion Electrochemistry-Worksheet JEE Advance/AIIMS 40. 41. 42. 43. 44. 45. 46. 47. 6 Adding powdered lead and iron to a solution that is 1.0 M in both Pb2+ and Fe2+ ions, would result a reaction, in which…(E° Pb2+/Pb = − 0.126 V and E° Fe2+/Fe = −0.440 V) [CPMT 1987] 2+ (a) More iron andPb ions are formed (b) More lead and Fe2+ ions are formed (c) Concentration of both Pb2+and Fe2+ ions increases (d) There is no net change When compared to ∆G ° for the formation of Al2O3, the ∆G ° for the formation of Cr2O3 is… [KCET 2008] (a) Same (b) Unpredicted (c) Higher (d) Lower Reduction potential of four elements P, Q, R, S is –2.90, +0.34, +1.20 and –0.76. Reactivity decreases in the order … [MP PET 1989; UPSEAT 2001] (a) P > Q > R > S (b) Q > P > R > S (c) R > Q > S > P (d) P > S > Q > R Standard electrode potential of Ag+/ Ag and Cu+/Cu is +0.80V and + 0.34 V respectively. These electrodes are joint together by salt bridge if… [AMU 2002] (a) Silver electrode work like anode, then E0cell is – 0.34 V (b) Copper electrode work like anode, then E0cell is + 0.46 V (c) Silver electrode work like cathode, then E0cell is – 0.34 V (d) Silver electrode work like anode, then E0cell will be + 1.14 V The reaction is spontaneous if the cell potential is… [MP PET 1999] (a) Positive (b) Negative (c) Zero (d) Infinte The equilibrium constant of the following redox reaction at 298 K is 1 × 108 ; 2Fe3+(aq) + 2I– (aq) ↔ 2Fe2+(aq) + I2(s). If the standard reduction potential of iodine becoming iodide is + 0.54 V, what is the standard reduction potential of Fe3+/ Fe2+. [Kerala PMT 2008] (a) + 1.006V (b) – 1.006 V (c) + 0.77 V (d) – 0. 77 V (e) – 0.652 V Iron displaces copper from its salt solution, because… [MP PMT 1996] (a) Atomic number of iron is less than that of copper (b) The standard reduction potential of iron is less than that of copper (c) The standard reduction potential of iron is more than that of copper (d) The iron salt is more soluble in water than the copper salt. (i) Copper metal dissolves in 1M silver nitrate solution and crystals of silver metal get deposited (ii) Silver metal does not react with 1M zinc nitrate solution (iii) Zinc metal dissolves in 1M copper sulphate solution and copper metal gets deposited Hence the order of decreasing strength of the three metals as reducing agents will be Electrochemistry-Worksheet JEE Advance/AIIMS 48. 49. (a) Cu > Ag > Zn (b) Ag > Cu > Zn (c) Zn > Cu > Ag (d) Cu > Zn > Ag Calculate standard free energy change for the reaction 1 1 1 Cu ( s ) + Cl2 ( g ) Cu 2 + + Cl − taking place at 25 0C in a cell whose standard e.m.f. 2 2 2 is 1.02 volts … [MP PMT 1997] (a) –98430 J (b) 98430 J (c) 96500 J (d) – 49215 J 0 0 Given EFe3+ /Fe = − 0.036V , EFe2+ /Fe = − 0.439V . The value of standard electrode potential for the change Fe(3aq+ ) + e − → Fe 2 + ( aq ) will be… 50. 51. 52. 53. 54. 7 [AIEEE 2009] (a) – 0.072 V (b) 0.385 V (c) 0.770 V (d) −0.270 V Which one of the following statements is correct…? [MP PET 1997] (a) The oxidation number of oxygen in KO2 is zero (b) The specific conductance of an electrolyte solution decreases with increase in dilution (c) Sn2+ oxidises Fe3+ (d) Zn/ZnSO4 is a reference electrode In infinite dilutions, the equivalent conductances of Ba2+ and Cl– are 127 and 76 ohm–1 cm–1 equt–1. The equivalent conductivity of BaCl2 at indefinite dilution is… [CBSE 2000] (a) 101.5 (b) 139. 5 (c) 203.5 (d) 279.5 The factor which is not affecting the conductivity of any solution is (a) Dilution (b) Nature of electrolyte (c) Temperature (d) None of these The conductivity of strong electrolyte is… [KCET 1993; CPMT 2003] (a) Increase on dilution slightly (b) Decrease on dilution (c) Does not change with dilution (d) Depend upon density of electrolytes itself If X is the specific resistance of the solution and M is the molarity of the solution, the molar conductivity of the solution is given by… [Kurukshetra CEE 2002] 1000X 1000 (a) (b) M MX 1000M MX (c) (d) X 1000 Electrochemistry-Worksheet JEE Advance/AIIMS 55. 56. 57. 58. 59. 60. 61. 62. 8 If one end of a piece of a metal is heated, the other end becomes hot after some time. This is due to … [CBSE PMT 1995] (a) Energised electrons moving to the other part of the metal (b) Resistance of the metal (c) Mobility of atoms in the metal (d) Minor perturbation in the energy of atoms Conductivity of a solution is directly proportional to… [KCET 1984] (a) Dilution (b) Number of ions (c) Current density (d) Volume of the solution The increase in equivalent conductance of an electrolyte solution with dilution is due to the increase in… [MP PMT 1996] (a) Ionic attraction (b) Molecular attraction (c) Degree of association of the electrolyte (d) Degree of ionization of the electrolyte Which of the following conducts electricity…? [AFMC 1995] (a) Fused NaCl (b) CO2 (c) Br2 (d) Si It has been observed that gaseous hydrogen chloride is a very poor conductor of electricity but a solution of hydrogen chloride gas in water is a good conductor of electricity. This is due to the fact that (a) Water is good conductor of electricity (b) Hydrogen chloride gas in water solution ionizes (c) A gas is non-conductor but a liquid conducts electricity (d) Gas does not obey Ohm’s law whereas solution does Electrolytic conduction differs from metallic conduction in that in the case of electrolytic conduction…. [KCET 1987; Bihar CEE 1992] (a) The resistance increases with increasing temperature (b) The resistance decreases with increasing temperature (c) The flow of current does not generate heat (d) The resistance is independent of the length of the conductor. The electrolytic conductance is a direct measure of… [KCET 1990; CPMT 2003] (a) Resistance (b) Potential (c) Concentration (d) Dissociation What is the effect of dilution on the equivalent conductance of strong electrolyte… [RPMT 2006] (a) Decrease on dilution (b) Remains unchanged (c) Increase on dilution (d) None of the above Electrochemistry-Worksheet JEE Advance/AIIMS 63. 64. 65. 66. 67. 68. 69. 70. 71. 9 Which of the following statements is not applicable to electrolytic conductors…? [AIIMS 1991] (a) New products show up at the electrodes (b) Ions are responsible for carrying the current (c) Show a positive temperature coefficient for conductance (d) A single stream of electrons flows from cathode to anode Which one is not a conductor of electricity… [RPET 1999] (a) NaCl (aqueous) (b) NaCl (solid) (c) NaCl (molten) (d) Ag metal The molar conductivities of KCl, NaCl and KNO3 are 152, 128 and 111 S cm–1 mol–1 respectively. What is the molar conductivity of NaNO3… [VITEEE 2008] 2 –1 (a) 101 S cm mol (b) 87 S cm2 mol–1 (c) – 101 S cm2 mol–1 (d) – 391 S cm2 mol–1 Which of the following is a poor conductor of electricity…? [EAMCET 1992] (a) CH3COONa (b) C2H5OH (c) NaCl (d) KOH Given l / a = 0.5 cm–1. R = 50 ohm, N = 1.0. The equivalent conductance of the electrolytic cell is… [Orissa JEE 2005] –1 2 –1 (a) 10 ohm cm gm eq (b) 20 ohm–1 cm2 gm eq–1 –1 2 –1 (c) 300 ohm cm gm eq (d) 100 ohm–1 cm2 gm eq–1 If equivalent conductance of 1M benzoic acid is 12.8 ohm–1cm2 and if the conductance of benzoate ion and H+ ion are 42 and 288.42 ohm–1cm2 respectively. Its degree of dissociation is… [DPMT 2005] (a) 39% (b) 3.9% (c) 0.35% (d) 0.039% –1 The unit ohm is used for … [J & K 2005] (a) Molar conductivity (b) Equivalent conductivity (c) Specific conductivity (d) Conductivity What a solution of an electrolyte is heated the conductance of the solution… [KCET 1991] (a) Increases because of the electrolyte conduct better (b) Decrease because of the increased heat (c) Decreases because of the dissociation of the electrolyte is suppressed (d) Increases because the electrolyte is dissociated more What is the % dissociation of CH3COOH, if equivalent conductivity at this dilution and at infinite dilution is 148 and 398 S cm2/mol respectively… [AMU 2006] (a) 37.18% (b) 47% (c) 48.78% (d) 10.8% Electrochemistry-Worksheet JEE Advance/AIIMS 72. 73. Molar conductance of electrolytic solution Λm is … [DCE 2007] (a) ∝ l (b) ∝ (1/A) (c) ∝ (1/C) (d) ∝ ( C ) At 25 0C, 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. λm0 Ba ( OH ) 2 in S m2mol–1 is … 10–4 (a) 52.4 × (c) 402 × 10–4 74. 75. 76. 77. 78. 79. 80. 10 [EAMCET 2009] (b) 524 × 10–4 (d) 262 × 10–4 M solution of a weak monobasic acid is 8.0 mhos 32 cm2 and at infinite dilution is 400 mhos cm2. The dissociation constant of this acid is… [CBSE PMT 2009] (a) 1.25 × 10–5 (b) 1.25 × 10–6 (c) 6.25 × 10–4 (d) 1.25 × 10–4 The correct expression in SI system relating the equivalent conductance (λC), specific conductance ( κ ) and equivalent concentration (C) is… Where C is the number of gm equivalents in one litre of the solution. [J & K 2009] κ 1000 (a) λC = (b) λC = κ × C C −3 κ × 10 κ × 10 −6 (c) λC = (d) λC = C C –1 The specific conductance of a solution is 0.2 ohm cm–1 and conductivity is 0.04 ohm–1. The cell constant would be… [RPET 1999] –1 (a) 1 cm (b) 0 cm–1 (d) 0.2 cm–1 (c) 5 cm–1 If the conductance and specific conductance of a solution is one then its cell constant would be… [RPET 1999] (a) 1 (b) Zero (c) 0.5 (d) 4 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 is… [CBSE PMT 1997; DCE 2009] –1 2 –1 (a) 201. 28 ohm cm mol (b) 390.71 ohm–1 cm2 mol–1 (c) 698.28 ohm–1 cm2 mol–1 (d) 540.48 ohm–1 cm2 mol–1 The electrodes of a conductivity cell are 3 cm apart and have a cross-sectional area of 4 cm2. The cell constant of the cell (in cm–1) is (a) 4 × 3 (b) 4 / 3 (c) 3 / 4 (d) 9 / 4 In the electrolysis of aqueous solution of CuSO4 using copper electrodes, the process that takes place at the anode is [J & K 2009] (a) SO42– → SO4 + 2e– (b) Cu → Cu + + e – – – (c) 2OH → H2O + ½ O2 +2e (d) Cu → Cu2+ + 2e– Electrochemistry-Worksheet JEE Advance/AIIMS The equivalent conductance of 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 11 Strong electrolytes are those which... [MNR 1983; AMU 1983, 84] (a) Dissolve readily in water (b) Conduct electricity (c) Dissociate into ions at high dilution (d) Completely dissociate into ions at all dilutions Electrolyte can conduct electricity because (a) Their molecules contain unpaired electrons, which are mobile (b) Their molecules contain loosely held electrons which get free under the influence of voltage (c) The molecules break up into ions when a voltage is applied (d) The molecules are broken up into ions when the electrolyte is fused or is dissolved in the solvent Which one of the following metals could not be obtained on electrolysis of aqueous solution of its salts…? [IIT 1990] (a) Ag (b) Mg (c) Cu (d) Cr Which of the following aqueous solution will conduct an electric current quite well…? [MP PMT 1987] (a) Glycerol (b) HCl (c) Sugar (d) Pure water On the electrolysis of aqueous solution of sodium sulphate, on cathode we get… [MP PMT 1992, 2002] (a) Na (b) H2 (c) SO2 (d) SO3 Electrolysis involves oxidation and reduction respectively at… [AMU 1983, MH CET 2001] (a) Anode and cathode (b) Cathode and anode (c) At both the electrodes (d) None of the above Which of the following compounds will not undergo decomposition on passing electricity through aqueous solution…? [AMU 1982, 83; MP PET 2001] (a) Sugar (b) Sodium Chloride (c) Sodium Bromide (d) Sodium Acetate During the electrolysis of an electrolyte, the number of ions produced, is directly proportional to the [AFMC 2002] (a) Time consumed (b) Electro chemical equivalent of electrolysis (c) Quantity of electricity passed (d) Mass of electrons On electrolysing a solution of dilute H2SO4 between platinum electrodes, the gas evolved at the anode is… [MNR 1980; CBSE PMT 1992] (a) SO2 (b) SO3 (c) O2 (d) H2 The products formed when an aqueous solution of NaBr is electrolysed in a cell having inert electrodes are… [AIIMS 2006] (a) Na and Br2 (b) Na and O2 (c) H2, Br2 and NaOH (d) H2 and O2 Electrochemistry-Worksheet JEE Advance/AIIMS 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 12 Electrolysis of aqueous HCl solution produces… [CPMT 1987] (a) H2 gas at the anode (b) H2 gas at the cathode (c) Cl2 gas at the cathode (d) Cl2 and O2 gases both at the anode During electrolysis of NaCl solution, part of the reaction is Na+ + e– → Na. This is termed as (a) Oxidation (b) Reduction (c) Deposition (d) Cathode reaction Brine solution (sea water) on electrolysis will not give… [DCE 2006] (a) NaOH (b) Cl2 (c) H2 (d) O2 The passage of current liberates H2 at cathode and Cl2 at anode. The solution is… [EAMCET 1987] (a) Copper chloride in water (b) NaCl in water (c) H2SO4 (d) Water Pure water does not conduct electricity because it… [Manipal MEE 1995] (a) Has a low boiling point (b) Is almost totally unionized (c) Is neutral (d) Is readily decomposed When 9.65 coulombs of electricity is passed through a solution of silver nitrate (atomic weight of Ag = 107.87 taking as 108) the amount of silver deposited is… [EAMCET 1992; KCET 2000] (a) 10.8 mg (b) 5.4 mg (c) 16.2 mg (d) 21.2 mg Three faradays electricity was passed through an aqueous solution of iron (II) bromide. The weight of iron metal (at. wt. = 56) deposited at the cathode (in gm) is… [EAMCET 1991] (a) 56 (b) 84 (c) 112 (d) 168 A silver cup is plated with silver by passing 965 coulombs of electricity, the amount of silver deposited [EAMCET 1990; MP PET 1994, 97] (a) 9.89 g (b) 107.87 g (c) 1.0787 g (d) 1.002 g The atomic weight of Al is 27. When a current of 5 Faradays is passed through a solution of Al+++ ions, the weight of Al deposited is (a) 27 gm (b) 36 gm (c) 45 gm (d) 39 gm The unit of electrochemical equivalent is… [EAMCET 1980] (a) Gram (b) Gram/ampere (c) Gram/coulomb (d) Coulomb/gram Electrochemistry-Worksheet JEE Advance/AIIMS 101. 102. 103. 104. 105. 106. 107. 108. 109. 13 If the current is passed into solution of an electrolyte… [AIIMS 1979] (a) Anions move towards anode, cations towards cathode (b) Anions and cations both move towards anode (c) Anions move towards cathode, cations towards anode (d) No movement of ions takes place Unit of Faraday is (a) Ampere (b) Coulomb (d) Coulomb sec–1 (c) Coulomb mole–1 On passing 0.1 Faraday of electricity through aluminium chloride, the amount of aluminium metal deposited on cathode is (Al = 27)… [MP PMT 1991] (a) 0.9 gm (b) 0.3 gm (c) 0.27 gm (d) 2.7 gm 5 amperes is passed through a solution of zinc sulphate for 40 minutes. Find the amount of zinc deposited at the cathode… [CBSE PMT 1996] (a) 40.65 gm (b) 4.065 gm (c) 0.4065 gm (d) 65.04 gm In an electroplating experiment ‘m’ g of silver is deposited, when 4 amperes of current flows for 2 minutes. The amount (in gms) of silver deposited by 6 amperes of current flowing for 40 seconds will be… [MNR 1991] (a) 4 m (b) m /2 (c) m /4 (d) 2 m On passing 3 amperes of electricity for 50 minutes, 1.8 gram metal deposits. The equivalent mass of metal is… [MP PMT 1992] (a) 20.5 (b) 25.8 (c) 19.3 (d) 30.7 The desired amount of charge for obtaining one mole of Al from Al 3+ (a) 3 × 96500 C (b) 96500 C 96500 96500 (c) C (d) C 3 2 On passing one faraday of electricity through the electrolytic cells containing Ag+, Ni+2 and Cr+3 ions solution, the deposited Ag (At. wt. = 108), Ni (At. wt. = 59) and Cr (At. wt. = 52) is [AIIMS 1982] Ag Ni Cr (a) 108 gm 29.5 gm 17.3 gm (b) 108 gm 59 gm 52.0 gm (c) 108.0 gm 108.0 gm 108.0 gm (d) 108 gm 117.5 gm 166.0 gm One Faraday of electricity when passed through a solution of copper sulphate deposits… [CPMT 1978] (a) 1 mole of Cu (b) 1 gm atom of Cu (c) 1 molecule of Cu (d) 1 gm equivalent of Cu Electrochemistry-Worksheet JEE Advance/AIIMS 110. 111. 112. 113. 114. 115. 116. 117. 118. 14 The platinum electrodes were immersed in a solution of cupric sulphate and electric current passed through the solution. After some time it was found that colour of copper sulphate disappeared with evolution of gas at the electrode. The colourless solution contains… (a) Platinum sulphate (b) Copper hydroxide (c) Copper sulphate (d) Sulphuric acid How many Faradays are required to generate one gram atom of magnesium from MgCl2… [MADT Bihar 1982] (a) 1 (b) 2 (c) 3 (d) 4 To deposit 0.6354 gm of copper by electrolysis of aqueous cupric sulphate solution, the amount of electricity required (in coulombs) is… [MP PMT 1989] (a) 9650 (b) 4825 (c) 3860 (d) 1930 The emf of the following Daniel cell at 298 K is E1. Zn/ZnSO4(0.01M) || CuSO4(1.0 M) | Cu When concentration of ZnSO4 is 1.0 and that of CuSO4 is 0.01 M, the emf is changed to E2. What is the relationship between E1 and E2 ? (a) E1 > E2 (b) E1 < E2 (d) E1 = 0 ≠ E2 (c) E1 = E2 The reduction potential of hydrogen electrode will be positive if (a) p(H2) = 1atm, [H+] = 1M (b) p(H2) = 2atm, [H+] = 2M (c) p(H2) = 2atm, [H+] = 1M (d) p(H2) = 2.3atm, [H+] = 1.5M Two platinum electrodes were immersed in a solution of CuSO4 and electric current was passed through the solution. After some time it was found that the colour of CuSO4 has disappeared with evolution of gas at the electrode. The colorless solution contains (a) platinum sulphate (b) copper hydroxide (c) sulphuric acid (d) cuprous sulphate + Consider the cell at 25°C Tl | Tl (0.001M) || Cu2+(0.10M) | Cu for which emf is 0.84 V. The emf of this cell could be increased by (a) increasing [Tl+] (b) increasing [Cu2+] (c) decreasing [Cu2+] (d) emf remains constant The electrode potential of silver electrode dipped in a 0.1M solution of silver nitrate at 25°C is (E°Ag | Ag+=0.80V) : (a) 0.0741V (b) 0.059V (c) 0.741 V (d) 0.859 V Salt of A(at. mass=7), B(at. mass=27) and C(at. mass=64) were electrolyzed under identical condition using same quantity of electricity. It was found that when 2.1 g of A was deposited, the weights of B and C deposited were 2.7 g and 9.6 g. The valences of A, B and C are respectively: (a) 3, 1 and 2 (b) 1, 3 and 2 (c) 3, 1 and 3 (d) 2, 3 and 2 Electrochemistry-Worksheet JEE Advance/AIIMS 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 15 The two platinum electrodes fitted in a conductance cell are 1.5 cm apart while the cross sectional area of each electrode is 0.75 cm2. The cell constant is: (a) 1.125 (b) 0.5 (c) 2.0 (d) 0.2 + 2+ For a cell reaction X + 2Y → X + 2Y Kc has been found to be 1012. The E°cell is: (a) 0.708 V (b) 1.36 V (c) 0.354 V (d) 1.006 V + For the cell reaction 4Br +O2 +4H → 2Br2 + 2H2O E°cell =0.16 V the value of log Kc is : (a) 108 (b) 10.8 (c) 5.4 (d) 1080 For an electrolytic solution of 0.05 mol L-1, the specific conductance has been found to be 0.0110 S cm-1. The molar conductance is : (a) 0.55 S cm2 mol-1 (b) 550 S cm2 mol-1 2 -1 (c) 0.22 S cm mol (d) 220 S cm2 mol-1 The molar conductivities of AB and AC electrolytes are 120 and 160 ohm1cm2mol-1 respectively. If ionic molar conductance of C is 120 ohm-1 cm2 mol-1, the ionic molar conductance of B is (a) 400 ohm-1cm2mol-1 (b) 40 ohm-1cm2mol-1 (c) 80 ohm-1cm2mol-1 (d) 160 ohm-1cm2mol-1 How many coulombs of electricity are required for the oxidation of 1 mole of H2O to O2? (a) 96500 C (b) 1.93 × 105 C (c) 4.83× 105 C (d) 9.65 × 106 C The molar conductance of a 0.1 M solution of an electrolyte was found to be 400 ohm-1cm2mol-1. The cell constant of the cell is 0.1 cm-1. The resistance of the solution is: (a) 25 ohm (b) 2000 ohm (c) 200 ohm (d) 400 ohm The molar conductances of CH3COONa, HCl and NaCl at infinite dilution are 91, 426 and 126 S cm2 mol-1 respectively at 25°C. The molar conductance at infinite dilution for CH3COOH would be (a) 209 S cm2 mol-1 (b) 391 S cm2 mol-1 (c) 461 S cm2 mol-1 (d) none of these What weight of copper will be deposited by passing 2 Faradays of electricity through a cupric acid (At. mass = 63.5)? (a) 63.5 g (b) 31.75 g (c) 127 g (d) 2.0 g The solution of copper sulphate in which copper rod is dipped is diluted to 10 times. The reduction potential of copper (a) Decreases by about 60 mV (b) Decreases by about 30 mV (c) Decreases by about 30 V (d) Increases by about 30 mV If a salt bridge is removed between two half cells in an experiment, the voltage (a) Does not change (b) Increases rapidly (c) Decreases slowly (d) Falls to zero Electrochemistry-Worksheet JEE Advance/AIIMS 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 16 When lead storage battery is charged, it acts as (a) fuel cell (b) an electrolytic cell (c) a galvanic cell (d) a concentration cell Which of the following solutions will have highest equivalent conductance? (a) 0.01 M NaCl (b) 0.050 M NaCl (c) 0.005 M NaCl (d) 0.02 M NaCl The standard electrode potential values of the element A, B and C are 0.68, -2.50 and -0.50 V respectively. The order of their reducing power is : (a)A > B > C (b) A > C >B (c) C > B > A (d) B > C > A Two electrolytic cell, one containing acidified ferrous sulphate and other containing acidified ferric sulphate are connected in series. The ratio of iron deposited at cathodes in the two cell will be respectively (a) 2 : 1 (b) 2 : 3 (c) 1 : 1 (d) 3 : 2 Which one of the following will increase the voltage of the cell? Sn(s) + 2Ag+(aq) → Sn2+(aq) + 2Ag(s) (a) Increase in the size of the silver rod (b) Increase in the concentration of Sn2+ ion (c) Increase in the concentration of Ag+ ions (d) None of the above The following four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue ? The oxidation potentials of Zn, Ag, Cd and Pb are +0.76, -0.80, +0.40 and +0.13 respectively (a) Zn(NO3)2 (b) AgNO3 (c) Cd(NO3)2 (d) Pb(NO3)2 A solution of sodium sulphate in water is electrolyzed using inert electrodes. The products at the cathode and anode are respectively (a) H2, SO2 (b) O2, H2 (c) O2, Na (d) O2, SO2 As a lead storage battery is charged (a) Lead dioxide dissolves (b) Sulphuric acid is regenerated (c) The lead electrode becomes coated with PbSO4 (d) The amount of H2SO4 decreases On dilution of the molar conductance of an electrolyte (a) Increases (b) Decreases (c) Remains unaffected (d) May decrease or increase An electric current is passed through silver voltmeter connected to a water voltmeter weighed 0.108 g more at the end of electrolysis. The volume of oxygen evolved at STP is (a) 56 cm3 (b) 550 cm3 3 (c) 5.6 cm (d) 11.2 cm3 Electrochemistry-Worksheet JEE Advance/AIIMS 140. 141. 142. 143. 144. 145. 146. 147. 148. 17 If three Faradays of electricity is passed through the solutions of AgNO3, CuSO4 and AuCl3, the molar ratio of the cations deposited at the cathodes will be (a) 1 : 1 : 1 (b) 1 : 2 : 3 (c) 3 : 2 : 1 (d) 6 : 3 : 2 The specific conductance of a 0.1N KCl solution at 23°C is 0.012 ohm-1cm-1. The resistance of the cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be (a) 0.142cm-1 (b) 0.616cm-1 (c) 0.918cm-1 (d) 1.12cm-1 In which cell, the free energy of a chemical reaction is directly converted into electricity? (a) Leclanche cell (b) Concentration cell (c) Fuel cell (d) Lead storage battery A gas X at 1 atm is bubbled through a solution containing a mixture of 1 M Y and 1 M Z at 25°C. If the reduction potential of Z > Y > X, then (a) Y will oxidize X and not Z (b) Y will oxidize Z and not X (c) Y will oxidize both X and Z (d) Y will reduce both X and Z 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 (a) +0.49 V (b) + 0.38 V (c) −0.19 V (d) − 0.38 V + For the electrochemical cell, M | M || X | X, E°(M+/M)=0.44 V and E°(X/X ) =0.33 V. From this data, one can deduce that (a) M + X → M+ + X is the spontaneous reaction (b) M+ + X → M + X is the spontaneous reaction (c) Ecell = 0.77 V (d) Ecell = −0.77 V The amount of an ion discharged during electrolysis is not dependent of : (a) Resistance of solution (b) Time (c) Current strength (d) Electrochemical equivalent of element Which aqueous solution will conduct an electric current quite well ? (a) Glycerol (b) Sugar (c) Hydrochloric acid (d) Pure water The unit of electrochemical equivalent is : (a) gram (b) gram/ampere (c) gram/coulomb (d) coulomb/gram Electrochemistry-Worksheet JEE Advance/AIIMS 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. 159. 18 Each of the three metals X, Y and Z were put in turn into aqueous solution of the other two. Reduction potential of three metals are Z > Y > X. X + Salt of Y (or Z) = Y (or Z) + Salt of X. Which observation is probably incorrect? (a) Y + Salt of X = No action observed (b) Y + Salt of Z = Z + Salt of Y (c) Z + Salt of X = X + Salt of Z (d) Z + Salt of Y = No action observed Molten NaCl conducts electricity due to the presence of : (a) Free electrons (b) Free molecules (c) Free ions (d) Atoms of Na and Cl Faraday’s law of electrolysis fails when : (a) Temperature is increased (b) Inert electrodes are used (c) A mixture of electrolytes is used (d) In none of the above cases The electrolysis of a solution resulted in the formation of H2 at the cathode and Cl2 at the anode. The liquid is : (a) Pure water (b) H2SO4 solution (c) NaCl solution in water (d) CuCl2 solution in water In Dow’s method, sodium is prepared by the electrolysis of molten NaCl. The reaction at cathode is : (a) 2Cl– → Cl2(g) + 2e (b) Na+ + e → Na(s) (c) Na+ (aq) + e → Na+ + e (d) Na+(aq) + e → Na(s) The reaction, Cu2+ (aq) + 2Cl– (aq)→ Cu(s) + Cl2 (g) has E0cell = -1.03 V. This reaction : (a) Can be made to produce electricity in voltaic cell (b) Can be made to occur in an electrolytic cell (c) Can occur in acidic medium only (d) Can occur in basic medium only The best conductor of electricity is 1 M solution of : (a) CH3COOH (b) H2SO4 (c) H3PO4 (d) Boric acid For which cell e.m.f. is independent of the concentrations of electrolytes used ? (a) Fe | FeO(s) | KOH(aq) | NiO(s)|Ni2O3(s)| Ni (b) Pt (H2) | HCl| Pt (Cl2) (c) Zn|Zn(NO3)2 ||CuSO4|Cu (d) Hg, HgCl2 | KCl || AgNO3 | Ag Which metal can deposit copper from copper sulphate solution ? (a) Mercury (b) Iron (c) Gold (d) Platinum If a salt bridge is removed from the two half cells, the voltage : (a) Drops to zero (b) Does not change (c) Increases gradually (d) Increases rapidly In an aqueous solution, hydrogen (H2) will not reduce : (a) Fe3+ (b) Cu2+ 2+ (c) Zn (d) Ag+ Electrochemistry-Worksheet JEE Advance/AIIMS 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. 171. 19 Which reaction occur at cathode during electrolysis of fused lead bromide? (a) Pb → Pb2+ + 2e (b) Br + e→ Br– – (c) Br → Br + e (d) Pb2+ + 2e→ Pb In a salt bridge, KCl is used because : (a) It is an electrolyte (b) It is good conductor of electricity (c) The transport number of K+ and Cl– ions are nearly same or both have same ionic mobility. (d) It is ionic compound Indicator electrode is : (a) SHE (b) Calomel electrode (c) Ag/AgCl electrode (d) Quinhydrone electrode 2+ 3+ In the reaction, 2Al + 3Fe → 2Al + 3Fe possible ? (a) No, because standard oxidation potential of Al < Fe (b) Yes, because standard oxidation potential of Al > Fe (c) Neither (a) nor (b) (d) Data are unpredictable The element that is easiest to be reduced is : (a) Fe (b) Cu (c) Ag (d) Sn A dilute solution of Li2SO4 is electrolysed. The products formed at the anode and cathode, respectively are : (a) S and Li (b) O2 and Li (c) SO2 and O2 (d) O2 and H2 Which metal will dissolve, if the cell works Cu | Cu2+ || Ag+ |Ag ? (a) Cu (b) Ag (c) Both (a) and (b) (d) None of these In the concentration cells, the electrical energy is produced due to : (a) Oxidation of fuel (b) Heat energy (c) Chemical reaction (d) Transfer of a substance from one concentration to other The number of faraday required to liberate 1 mole of any element indicates : (a) Weight of element (b) Conductance of electrolyte (c) Charge on the ion of that element (d) None of the above For a redox reaction to proceed spontaneously in a given direction, the e.m.f. should : (a) be zero (b) have +ve sign (c) have –ve sign (d) have either +ve or –ve sign KCl (aq) cannot be used as a salt bridge for the cell Cu(s) |CuSO4 (aq) || AgNO3 (aq) |Ag (s) because : (a) CuCl2 is precipitated (b) Cl2 gas is given out (c) AgCl is precipitated (d) All of these The electrode potential of a glass electrode depends upon : (a) Concentration of chloride ions (b) Concentration of hydrogen ions (c) Concentration of KCl solution (d) None of the above Electrochemistry-Worksheet JEE Advance/AIIMS 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 20 Which solution will show highest resistance during the passage of current? (a) 1 N NaCl (b) 0.1 N NaCl (c) 2 N NaCl (d) 0.05 N NaCl Which represents disproportionation ? (a) 2Cu+ →Cu2+ + Cu (b) 3I2→ 5I– + I 5+ (c) H2O + Cl2 → Cl– + ClO– + 2H+ (d) All of the above The oxidation potential of Mg and Al are +2.37 and +1.66 volt respectively. The Mg in chemical reactions : (a) Will be replaced by Al (b) Will replace Al (c) Will not be able to replace Al (d) None of the above The factor temperature coefficient for e.m.f. is : (a) (δE /δT)P (b) (δE /δP)T (d) None of these (c) (δE /δV)T 3 faraday of electricity is passed through molten Al2O3, aqueous solution of CuSO4 and molten NaCl taken in three different electrolytic cell. The amount of aluminium, copper and sodium deposited at the cathode will be in the ratio of : (a) 1 mole : 2 mole : 3 mole (b) 1.5 mole : 2 mole : 3 mole (c) 1 mole : 1.5 mole : 3 mole (d) 1 mole : 3 mole : 2 mole The reduction potentials of four metals P, Q, R and S are – 2.90, + 0.34, + 1.20 and – 0.76 respectively. Reactivity decreases in the order : (a) P > Q > R > S (b) Q > P > R > S (c) R > Q > S > P (d) P > S > Q > R Which metal does not give the following reaction ? M + water or steam → oxide + H2 ↑ (a) Iron (b) Sodium (c) Mercury (d) Magnesium A galvanic cell is composed of two hydrogen electrodes, one of which is a standard one. In which of the following solutions should the other electrode be immersed to get maximum e.m.f. ? (a) 0.1 M HCl (b) 0.1 M CH3COOH (c) 0.1 M H3 PO4 (d) 0.1 M H2SO4 The thermodynamic efficiency of cell is given by : (a) ∆H / ∆G (b) nFE /∆G (c) nFE / ∆H (d) nFE0 E0 of an electrode is : (a) Extensive property (b) Constitutive property (c) Colligative property (d) Additive property 2+ Standard electrode potentials of Fe + 2e → Fe and Fe+ + 3e → Fe are – 440 V and – 0.036 V respectively. The standard electrode potential (E0) for Fe3+ + e → Fe2+ is : (a) – 0.476 V (b) – 0.404 V (c) + 0.404 V (d) +0.772 V Electrochemistry-Worksheet JEE Advance/AIIMS 183. 184. 185. 186. 187. 188. 189. 190. 191. 21 1 mole of Al is deposited by X coulomb of electricity passing through aluminium nitrate solution. The number of mole of silver deposited by X coulomb of electricity from silver nitrate solution is : (a) 3 (b) 4 (c) 2 (d) 1 Copper from copper sulphate solution can be displaced by … The standard reduction potentials of some electrodes are given below. E0 (Fe2+ , Fe) = – 0.44 V ; E0 (Zn2+ , Zn) = – 0.76 V ; E0 (Cu2+ , Cu) = + 0.34 V ; E0 (Cr3+ , Cr) = – 0.74 V ; 1 E0 H 3 O + , H 2 = –0.00V 2 (a) H2 (b) Zn (c) Cr (d) Fe (e) All The number of faraday required to generate 1 g-atom of Mg from MgCl2 is (a) 1 (b) 2 (c) 3 (d) 4 2 3 E.M.F. of cell Ni || Ni + (1.0 M) || Au + (1.0 M) | Au is ….. If E0 for Ni2+ | Ni is – 0.25 V, E0 for Au3+ | Au is 1.50 V. (a) + 1.25 V (b) – 1.75 V (c) + 1.75 V (d) + 4.0 V 0 E for the half cell reactions are as, Zn = Zn2+ + 2e; E0 = + 0.76 V; Fe = Fe2+ + 2e; E0 =+ 0.41 V. The E0 for the cell reaction, Fe2+ + Zn → Zn2+ + Fe is : (a) – 0.35 V (b) + 0.35 V (c) + 1.17 V (d) – 0.17 V A certain current liberates 0.504 g of hydrogen in 2 hr. How many gram of copper can be liberated by the same current flowing for the same time in CuSO4 solution ? (a) 12.7 (b) 16 (c) 31.8 (d) 63.5 Passage of three faraday of charge through aqueous solution of AgNO3, CuSO4, Al(NO3)3 and NaCl will deposit metals at the cathode in the molar ratio of : (a) 1 : 2 : 3 : 1 (b) 6 : 3 : 2 : 6 (c) 6 : 3 : 0 : 0 (d) 3 : 2 : 1 : 0 0 The standard potentials at 25 C for the following half reactions are given below, Zn2+ + 2e →Zn ; E0 = – 0.762 V ; Mg2+ + 2e → Mg : E0 = – 2.37 V When zinc dust is added to the solution of MgCl2 : (a) ZnCl2 is formed (b) Zinc dissolves in the solution (c) No reaction takes place (d) Mg is precipitated Normal Al–AlCl3 coupled with normal hydrogen electrode gives an e.m.f. of 1.66 V. The standard oxidation electrode potential of aluminium is : (a) – 1.66 V (b) + 1.66 V (c) – 0.83 V (d) + 0.83 V Electrochemistry-Worksheet JEE Advance/AIIMS 192. 193. 194. 195. 196. 197. 198. 199. 200. 201. 22 The cell reaction for the given cell is spontaneous if : PtCl2 |Cl– (1M) || Cl– (1 M)| PtCl2 P1 P2 (a) P1 > P2 (b) P1 < P2 (c) P1 = P2 (d) P2 = 1 atm On passing electricity through dilute H2SO4 solution the amount of substance liberated at the cathode and anode are in the ratio : (a) 1 : 8 (b) 8 : 1 (c) 16 : 1 (d) 1 : 16 During electrolysis of an aqueous solution of Cu2+ sulphate, 0.635 g of copper was deposited at cathode. The amount of electricity consumed in coulomb is : (a) 1930 (b) 3860 (c) 9650 (d) 4825 If Mg2+ + 2e → Mg(s) ; E = – 2.37 V, Cu2+ + 2e → Cu(s) ; E = +0.34 V ? The e.m.f. of the cell Mg | Mg2+ || Cu2+ | Cu is : (a) 2.71 V (b) 2.30 V (c) 2.80 V (d) 1.46 V A certain quantity of electricity is passed through aqueous solution of AgNO3 and CuSO4 connected in series. If Ag (at. wt. 108) deposited at the cathode is 1.08 g then Cu deposited at the cathode is (at. wt. of Cu is 63.53) : (a) 6.354 g (b) 0.317 g (c) 0.6354 g (d) 3.177 g The number of electrons passing per second through a cross-section of Cu wire carrying 10 ampere is : (a) 6 × 1019 (b) 8 × 1019 19 (d) 1.6 × 1019 (c) 1 × 10 The same amount of electricity was passed through two cells containing molten Al2O3 and molten NaCl. If 1.8 g of Al were liberated in one cell, the amount of Na liberated in the other cell is : (a) 4.6 g (b) 2.3 g (c) 6.4 g (d) 3.2 g In the electrolysis of CuCl2 solution using Cu electrodes the mass of cathode increases by 3.18 g. What happened at the other electrode ? (a) 0.05 mole of Cu2+ ions passed into solution (b) 0.112 litre of Cl2 was liberated (c) 0.56 litre O2 was liberated (d) 0.56 litre O2 was liberated (d) 0.1 mole of Cu2+ ions passed into the solution Number of faraday required to liberate 8 g of H2 is : (a) 8 (b) 16 (c) 4 (d) 2 The weight ratio of Al and Ag deposited using the same quantity of current is : (a) 9 : 108 (b) 2 : 12 (c) 108 : 9 (d) 3 : 8 Electrochemistry-Worksheet JEE Advance/AIIMS 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 23 20 g of chlorine are evolved in 6 hour from sodium chloride solution by the current of : (a) 5 ampere (b) 10 ampere (c) 2.5 ampere (d) 50 ampere What weight of copper will be deposited by passing 2 faraday of electricity through a solution of Cu (II) salt ? (a) 35.6 g (b) 63.5 g (c) 6.35 g (d) 3.56 g Passage of 1 faraday of electricity through a solution of CuSO4, deposits : (a) 1 mole of Cu (b) 1 g atom of Cu (c) 1 molecule of Cu (d) 1 g equivalent of Cu The amounts of sodium deposited by 5 ampere current for 10 minute from fused NaCl is : (a) 0. 715 g (b) 71.5 g (c) 5.17 g (d) 0.517 g –2 10 g atom of Ag can be oxidised to Ag+ during the electrolysis of AgNO3 solution using silver electrode by : (a) 965 coulomb (b) 96500 coulomb (c) 9650 coulomb (d) 96.500 coulomb How many coulomb of electricity are consumed when 100 mA current is passed through a solution of AgNO3 for 30 minute during an electrolysis experiment ? (a) 108 (b) 18000 (c) 180 (d) 3000 Total charge on 1 mole of a monovalent metal ion is equal to : (a) 6.28 × 1018 coulomb (b) 1.6 × 10–19 coulomb (c) 9.65 × 104 coulomb (d) None of these The amount of energy expanded during the passage of one ampere current for 100 second under a potential of 115 V is : (a) 20 kJ (b) 11.5 kJ (c) 115 kJ (d) 0.115 kJ Deduce from the following E0 values of half cells, what combination of two half cells would result in a cell with the largest potential ? (i) A + e → A– ; E0 = – 0.24 V (ii) B– + e → B2– ; E0 = + 1.25 V (iii) C– + 2e → C3– ; E0 = - 1.25 V (iv) D + 2e → D2– ; E0 = + 0.68 V (a) (ii) and (iii) (b) (ii) and (iv) (c) (i) and (iii) (d) (i) and (iv) 0 0 E for F2 + 2e = 2F is 2.8 V, E for ½ F2 + e = F– is : (a) 2.8 V (b) 1.4 V (c) – 2.8 V (d) – 1.4 V + 2+ For the cell, Tl | Tl (0.001M) || Cu (0.1 M) |Cu, Ecell at 250C is 0.83 V. Ecell can be increased : (a) By increasing [Cu2+] (b) By increasing [Tl+] 2+ (c) By decreasing [Cu ] (d) None of these Electrochemistry-Worksheet JEE Advance/AIIMS 213. 214. 215. 216. 217. 218. 219. 220. 221. 24 The charge required for the reduction of 1 mole of Cr2O72– ions to Cr3+ is : (a) 96500 C (b) 2 × 96500 C (c) 3 × 96500 C (d) 6 × 96500 C 10800 C of electricity on passing through the electrolyte solution deposited 2.977 of metal with atomic mass 106.4 g mol–1 the charge on the metal cation is : (a) + 4 (b) + 3 (c) +2 (d) +1 1 coulomb of charge passes through solution of AgNO3 and CuSO4 connected in series and the concentration of two solution being in the ratio 1 : 2. The ratio of amount of Ag and Cu deposited on Pt electrode is : (a) 107.9 : 63.54 (b) 54 : 31.77 (c) 107.9 : 31.77 (d) 54 : 63.54 During electrolysis of H2O, the molar ratio of H2 and O2 formed is : (a) 2 : 1 (b) 1 : 2 (c) 1 : 3 (d) 1 : 1 A hydrogen electrode placed in a buffer solution of CH3COONa and acetic acid in the ratio’s x : y and y : x has electrode potential values E1 volt and E2 volt respectively at 250C. The pKa values of acetic acid is (E1 and E2 are oxidation potential) : E + E2 E − E1 (a) 1 (b) 2 0.118 0.118 E1 + E2 E1 − E2 (c) − (d) 0.118 0.118 The weight of silver (eq. wt. = 108) displaced by that quantity of current which displaced 5600 mL of hydrogen at STP is : (a) 54 g (b) 108 g (c) 5.4 g (d) None of these The time required to coat a metal surface of 80 cm2 with 5 × 10–3 cm thick layer of silver (density 1.05 g cm–3) with the passage of 3A current through a silver nitrate solution is : (a) 115 sec (b) 125 sec (c) 135 sec (d) 145 sec Salts of A (atomic weight 7), B (atomic weight 27) and C (atomic weight 48) were electrolysed under identical conditions using the same quantity of electricity. It was found that when 2.1 g of A was deposited, the weights of B and C deposited were 2.7 g and 7.2 g. The valencies of A, B and C are respectively : (a) 3, 1 and 2 (b) 1, 3 and 2 (c) 3, 1 and 3 (d) 2, 3 and 2 To produce 160 g of oxygen, the number of mole of water required to be electrolysed is : (a) 2.5 (b) 5 (c) 10 (d) 20 Electrochemistry-Worksheet JEE Advance/AIIMS 222. 223. 224. 225. 226. 227. 228. 229. 25 A current is passed through two voltameters connected in series. The first voltameter contains XSO4 (aq) while the second voltameter contains Y2SO4 (aq). The relative atomic masses of X and Y are in the ratio of 2 : 1. The ratio of the mass of X liberated to the mass of Y liberated is : (a) 1 : 1 (b) 1 : 2 (c) 2 : 1 (d) none of these The standard oxidation potentials of the electrodes Ag | Ag+, Sn |Sn2+, Ca |Ca2+, Pb | Pb2+ are – 0.8, 0.136, 2.866 and 0.126 V respectively. The most powerful oxidising agent among these metal ions is : (a) Pb2+ (b) Ca2+ (c) Sn2+ (d) Ag+ Silver is removed electrolytically from 200 mL of a 0.1 N solution of AgNO3 by a current of 0.1 ampere. How long will it take to remove half of the silver from the solution ? (a) 10 sec (b) 16 sec (c) 100 sec (d) 9650 sec The atomic weight of Al is 27. When a current of 5 faraday is passed through a solution of Al3+ ions, the wt. of Al deposited is : (a) 27 g (b) 36 g (c) 45 g (d) 9 g Maximum number of mole of oxygen gas that can be obtained by the electrolytic decomposition of 90 g of water will be : (a) 1 (b) 2.5 (c) 5 (d) 9 0 + – For the reactions at 25 C, Ag (aq) + e = Ag(s); E0 = + 0.80 V Sn2+(aq) + 2e– = Sn(s) ; E0 = – 0.14 V What is the e.m.f. of the cell represented as Sn | Sn2+ || Ag+ | Ag ? If each ion having unit concentration: (a) 0.66 V (b) 0.80 V (c) 0.94 V (d) 1.08 V What is the potential of the cell containing two hydrogen electrodes as represented below, Pt ; ½ H2(g) | H+ (10–8 M) || H+ (0.001 M) | 1/2H2 (g) Pt ? (a) – 0.295 V (b) – 0.0591 V (c) 0.295 V (d) 0.0591 V Chromium plating can involve the electrolysis of an electrolyte of an acidified mixture of chromic acid and chromium sulphate. If during electrolysis the article being plated increases in mass by 2.6 g and 0.6 dm3 of oxygen are evolved at an inert anode, the oxidation state of chromium ions being discharged must be : (assuming Cr= 52 and 1 mole of gas at room temperature and pressure occupies a volume of 24 dm3) (a) –1 (b) zero (c) +1 (d) +2 Electrochemistry-Worksheet JEE Advance/AIIMS 230. 231. 232. A current of i ampere was passed for t second through three cells P, Q and R connected in series. These contain respectively silver nitrate, mercuric nitrate and Mercurous nitrate. At the cathode of the cell P, 0.216 g of Ag was deposited. The weights of mercury deposited in the cathode of Q and R respectively are : (a) 0.4012 and 0.8024 g (b) 0.4012 and 0.2006 g (c) 0.2006 and 0.4012 g (d) 0.1003 and 0.2006 g Two electrolytic cells, one containing acidified ferrous chloride and another acidified ferric chloride are connected in series. The ratio of iron deposited at cathodes in the two cells when electricity is passed through the cells will be : (a) 3 : 1 (b) 2 : 1 (c) 1 : 1 (d) 3 : 2 0 0 Given that E Fe3 +|Fe and E Fe2 +|Fe are – 0.36 V and – 0.439 V, respectively. The value of E0 Fe3 + ,Fe2 +|Pt would be : 233. 234. 235. 236. 237. 26 (a) (–36 – 0.439) V (b) [3(–0.36) +2 (–0.439)]V (c) ( – 0.36 + 0.439) V (d) [3 (– 0.36) –2 (– 0.439)] V The same amount of electricity was passed through two separate electrolytic cells containing solutions of nickel nitrate and chromium nitrate respectively. If 0.3 g of nickel was deposited in the first cell, the amount of chromium deposited is : (at. wt. Ni = 59, Cr = 52) (a) 0.1 g (b) 0.17 g (c) 0.3 g (d) 0.6 g Given electrode potentials are , Fe3+ + e → Fe2+ ; E0 = 0.771 V I2 + 2e → 2I– ; E0 = 0.536 V E0 cell for the cell reaction, 2Fe3+ + 2I– → 2Fe2+ + I2 is : (a) (2 × 0.771 – 0.536) = 1.006 V (b) (0.771 – 0.5 × 0.536) = 0.503 V (c) 0.771 – 0.536 = 0.235 V (d) 0.536 – 0.771 = – 0.235 V During electrolysis of fused sodium chloride, the reaction of the electrodes are : Anode Cathode + (a) Na + e → Na Cl– → ½ Cl +e (b) Na→ Na+ + e ½ Cl2 + e → Cl– (c) Cl– → ½ Cl2 + e Na+ + e → Na (d) ½ Cl2 + e → Cl– Na → Na+ + e The e. m. f. of the cell Zn | Zn2+ (1 M) || Cu2+ | Cu (1 M) is 1.1 volt. If the standard reduction potential of Zn2+ | Zn is – 0.78 volt, what is the oxidation potential of Cu|Cu2+ ? (a) + 1.86 V (b) 0. 32 V (c) – 0.32 V (d) – 1.86 V For I2 + 2e → 2I–, standard reduction potential = + 0.54 volt. For 2Br+ → Br2 + 2e–, standard oxidation potential = – 1.09 volt. For Fe → Fe2+ + 2e–, standard oxidation potential = + 0.44 volt. Which of the following reactions is nonspontaneous ? (a) Br2 + 2I– → 2 Br– + I2 (b) Fe + Br2 → Fe2+ + 2Br– (c) Fe + I2 → Fe2+ + 2I– (d) I2 + 2Br– → 2I– + Br2 Electrochemistry-Worksheet JEE Advance/AIIMS 238. 239. 240. 241. 242. 243. 244. 245. 246. 27 The hydrogen electrode is dipped in a solution of pH = 3 at 250C. The potential of the cell would be (the value of 2.303RT/F is 0.059 V) [KCET 1993, 2005] (a) 0.177 V (b) – 0.177 V (c) 0.087 V (d) 0.059 V The reaction Zn2+ + 2e– →Zn has a standard potential of – 0.76 V. This means [KCET 1992] (a) Zn can’t replace hydrogen from acids (b) Zn is a reducing agent (c) Zn is an oxidising agent (d) Zn2+ is a reducing agent 2H+(aq) + 2e– →H2(g). The standard electrode potential for the above reaction is (in volts) [CPMT 1988] (a) 0 (b) +1 (c) –1 (d) None of these K, Ca and Li metals may be arranged in the decreasing order of their standard [CPMT 1990] electrode potentials as (a) K, Ca, Li (b) Ca, K, Li (c) Li, Ca, K (d) Ca, Li, K The correct order of chemical reactivity with water according to electrochemical series [MP PMT 1991] (a) K > Mg > Zn > Cu (b) Mg > Zn > Cu > K (c) K > Zn > Mg > Cu (d) Cu > Zn > Mg > K Oxidation and reduction take place in a cell, then its electromotive force will be [RPET 1999] (a) Positive (b) Negative (c) Zero (d) Stable The standard electrode potential for the two electrode A+/A and B+/B are respectively 0.5 V and 0.75 V. The emf of the given cell A|A+ (a = 1) || B+ (a = 1) | B will be (a) 1.25 V (b) – 1.25 V (c) – 0.25V (d) 0.25 V 2+ Electrode potential of Zn /Zn is – 0.76 V and that of Cu2+/Cu is +0.34 V. The EMF of the cell constructed between these two electrodes is [KCET 1990; EAMCET 1992; MH CET 1999, 2003; AFMC 2001; CBSE PMT 2001; BHU 2001; Pb. CET 2002; Pb. PMT 2004; CPMT 2006] (a) 1.10 V (b) 0.42 V (c) –1.1V (d) – 0.42V EMF of a cell whose half cells are given below is Mg2+ + 2e–→Mg(s); E = – 2.37 V Cu2+ + 2e– → Cu(s); E = +0.33 V [EAMCET 1987; MP PET 1994; Pb. PMT 2000] (a) – 2.03 V (b) 1.36 V (c) 2.7 V (d) 2.03 V Electrochemistry-Worksheet JEE Advance/AIIMS 247. 248. 249. 250. 251. 252. 253. 254. 28 A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has EMF of 2.7 volts. If the standard reduction potential of copper electrode is +0.34 volt that of magnesium electrode is [KCET 1989] (a) + 3.04 volts (b) –3.04 volts (c) + 2.36 volts (d) – 2.36 volts Which substance eliminates bromine from KBr solution [IIT 1981; BVP 2003] (a) I2 (b) Cl2 (c) HI (d) SO2 In the electrochemical cell H2(g) 1 atm |H+(1M) || Cu2+ (1M) | Cu(s) Which one of the following statements is true [EAMCET 1997] (a) H2 is cathode; Cu is anode (b) Oxidation occurs at Cu electrode (c) Reduction occurs at H2 electrode (d) H2 is anode; Cu is cathode Amongst the following electrodes the one with zero electrode potential is [MP PMT 1997; Orissa JEE 2008] (a) Calomel electrode (b) Standard hydrogen electrode (c) Glass electrode (d) Gas electrode Which of the following is correct expression for electrode potential of a cell [MP PMT 1997] RT [ product ] RT [ product ] (a) E = E0 − ln (b) E = E0 + ln nF [ reactant ] F [reactant ] RT [ product ] RT [ reactant ] (c) E = E0 − ln (d) E = − ln nF [ product ] F [reactant ] E0 for the cell Zn|Zn2+(aq)||Cu2+(aq)|Cu is 1.10V at 250C, the equilibrium constant for the reaction Zn + Cu2+(aq) Cu + Zn2+ (aq) is of the order of [CBSE PMT 1997] –28 (a) 10 (b) 10–37 (c) 10+18 (d) 10+17 The e.m.f. of the cell in which the following reaction Zn (s) + Ni2+ (a=1.0) Zn2+ (a=10) + Ni(s) occurs, is found to be 0.5105 V at 298K. The standard e.m.f. of the cell is [Roorkee Qualifying 1998] (a) 0.5400 (b) 0.4810 V (c) 0.5696 V (d) – 0.5105 V The E0 for half cells Fe /Fe2+ and Cu/Cu2+ are – 0.44 V and +0.32 V respectively. Then [MP PMT 2003] 2+ (a) Cu oxidises Fe (b) Cu2+ oxidises Fe2+ (c) Cu oxidises Fe2+ (d) Cu reduces Fe2+ Electrochemistry-Worksheet JEE Advance/AIIMS 255. 256. 257. 258. 259. 260. The potential of the cell for the reaction M(s) + 2H+(1M) → H2(g), (1 atm) + M2+ (0.1 M) is 1.500 V. The standard reduction potential for M2+/M(s) couple is [AMU (Engg.) 2009] (a) 0.1470 V (b) 1.470 V (c) 14.70 V (d) None of these Given : (i) Cu2+ + 2e– → Cu, E0 = 0.337 V (ii) Cu2+ + 2e– → Cu+, E0 = 0.153 V Electrode potential E0 for the reaction, Cu+ + e– → Cu will be [CBSE PMT 2009; AMU PMT 2009] (a) 0.52 V (b) 0.90 V (c) 0.30 V (d) 0.38 V For a cell reaction involving a two-electron change, the standard emf of the cell is found to be 0.295 V at 250C. The equilibrium constant of the reaction at 250C will be [Roorkee 1999; AIEEE 2003; CBSE PMT 2004] –10 (b) 29.5 × 10–2 (a) 1 × 10 (c) 10 (d) 1 ×1010 Reduction potentials of A, B, C and D are 0.8 V, 0.79V, 0.34V and –2.37V respectively. Which element displaces all the other three elements [MP PET 2006] (a) B (b) A (c) D (d) C What is the potential of a cell containing two hydrogen electrodes the negative one in contact with 10–8 M H+ and positive one in contact with 0.025 M H+ [MP PMT 2000] (a) 0.18 V (b) 0.28 V (c) 0.38 V (d) 0.48 V + Cu ion is not stable in aqueous solution because of disproportionation reaction. E0 value for disproportionation of Cu+ is 0 0 = 0.15, ECu = 0.34V ) [IIT 1995] (Given ECu 2+ 2+ /Cu+ /Cu 262. (a) – 0.49 V (b) 0. 49 V (c) – 0. 38V (d) 0.38 V What is the potential of a half-cell consisting of zinc electrode in 0.01m ZnSO4 solution at 2580 C (E0 = 0.763V) [AIIMS 2000; BHU 2000] (a) 0.8221 V (b) 8.221 V (c) 0.5282 V (d) 9.232 V 0 0 If EFe2+ /Fe = −0.441V and EFe3+ /Fe2+ = 0.771V , the standard EMF of the reaction 263. Fe + 2 Fe 3+ → 3Fe 2 + will be [CBSE PMT 2006] (a) 1.212 V (b) 0.111 V (c) 0.330 V (d) 1.653 V 0 4+ 3+ For the cell reaction, 2Ce + Co → 2Ce + Co2+ E0Cell is 1.89V and ECo = −0.028. /Co2 + 261. 29 0 If ECe 4+ /Ce 3+ [Pb. CET 2000] (a) – 1.64 V (c) – 2.08 V (b) + 1.64 V (d) + 2.17 V Electrochemistry-Worksheet JEE Advance/AIIMS 264. Cr2O72 − + I − → I 2 + Cr 3+ 0 Ecell = 0.79V ; Ecr0 O2− = 1.33V , EI02 is 2 265. 266. [BVP 2004] 7 (a) – 0. 10 V (b) + 0.18 V (c) – 0. 54 V (d) + 0.54 V The rusting of iron takes place as follows 2H++ 2e– + 1/2O2 → H2O(l) ; E0 = + 1.23V Fe2++ 2e–→ Fe(s); E0 = – 0.44 V Calculate ∆G0 for the net process [IIT 2005] –1 (a) – 322 kJ mol (b) – 161 kJ mol–1 (c) – 152 kJ mol–1 (d) – 76 kJ mol–1 Ecell = 0.78 volt for the following cell. Fe(s) |Fe 2 +( aq ) ||Cu 2 + ( aq ) |Cu( s ) (xM ) 0 Fe /Fe 2 +( aq ) E 267. 268. 269. 270. 271. 30 (0.01 M ) 0 = 0.44 V , ECu /Cu2 + ( aq ) = −0.34V [Gujarat CET 2007] (a) x cannot be predicted (b) x = 0.01 M (c) x > 0.01 M (d) x < 0.01 M On the basis of the following E0 values, the strongest oxidizing agent is [Fe(CN)6]4- → [Fe(CN) 6]3– + e–1; E0 = – 0.35V Fe2+ → Fe3+ e– ; E0 = – 0.77V [CBSE PMT 2008] (a) Fe3+ (b) [Fe(CN)6]3– (c) [Fe(CN)6]4 (d) Fe2+ On passing C ampere of electricity through a electrolyte solution for t second, m gram metal deposits on cathode. The equivalent weight E of the metal is [MP PMT 1990] C ×t C ×m (a) E = (b) E = m × 96500 t × 96500 96500 × m C × t × 96500 (c) E = (d) E = C ×t m When 0.04 faraday of electricity is passed through a solution of CaSO4, then the weight of Ca2+ metal deposited at the cathode is [BHU 1996] (a) 0.2 gm (b) 0.4 gm (c) 0.6 gm (d) 0.8 gm How many atoms of calcium will be deposited from a solution of CaCl2 by a current of 25 milliamperes flowing for 60 seconds [BHU 1999] 18 (a) 4.68 × 10 (b) 4.68 × 1015 (c) 4.68 × 1012 (d) 4.68 × 109 On passing 0.5 faraday of electricity through NaCl, the amount of Cl deposited on cathode is [BHU 1997; RPET 1999] (a) 35.5 gm (b) 17.75 gm (c) 71 gm (d) 142 gm Electrochemistry-Worksheet JEE Advance/AIIMS 272. 273. 274. 275. 276. 277. 278. 279. 280. 31 What is the amount of chlorine evolved when 2 amperes of current is passed for 30 minutes in an aqueous solution of NaCl [BHU 1998; AIIMS 1999] (a) 66 g (b) 1.32 g (c) 33 g (d) 99 g On passing a current through KCl solution, 19.5 g of potassium is deposited. If the same quantity of electricity is passed through a solution of aluminium chloride, the amount of aluminium deposited is [EAMCET 1997] (a) 4.5 g (b) 9.0 g (c) 13.5 g (d) 27 g (e) None is correct A current being passed for two hour through a solution of an acid liberating 11.2 litre of oxygen at NTP at anode. What will be the amount of copper deposited at the cathode by the same current when passed through a solution of copper [BVP 2003] sulphate for the same time (a) 16 g (b) 63 g (c) 31.5 g (d) 8 g In a metal oxide, there is 20% oxygen by weight. Its equivalent weight is [Pb. PMT 2000] (a) 40 (b) 64 (c) 72 (d) 32 How much chlorine will be liberated on passing one ampere current for 30 minutes through NaCl solution [BVP 2003; BHU 2005] (a) 0.66 mole (b) 0.33 mole (c) 0.66 gm (d) 0.33 gm Calculate the volume of H2 gas at NTP obtained by passing 4 amperes through acidified H2O for 30 minutes is [DCE 2005] (a) 0.0836 L (b) 0.0432 L (c) 0.1672 L (d) 0.836 L 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 [EAMCET 1985] (a) 1.6 × 10–19 (b) 6 × 10–35 (c) 6 × 10–16 (d) 6 × 1012 When 96500 coulomb of electricity is passed through a copper sulphate solution, the amount of copper deposited will be [MP PMT 1996; Similar MP PMT 1995] (a) 0.25 mol (b) 0.50 mol (c) 1.00 mol (d) 2.00 mol During electrolysis of fused aluminium chloride 0.9 gm of aluminium was deposited on the cathode. The volume of chlorine liberated at the anode will be (a) 2.24 litres (b) 11.2 litres (c) 1.12 litres (d) 5.6 litres Electrochemistry-Worksheet JEE Advance/AIIMS 281. 282. 283. 284. 285. 286. 287. 288. 289. 32 The required charge for one equivalent weight of silver deposited on cathode is [Roorkee 1995] 7 (a) 9.65 × 10 C (b) 9.65 × 104 C (c) 9.65 × 103 C (d) 9.65 × 105 C Al2O3 is reduced by electrolysis at low potential and high currents. If 4.0 × 104 amperes of current is passed through molten Al2O3 for 6 hours, what mass of aluminium is produced (Assume 100% current efficiency, At.mass of Al =27 g mol–1) [CBSE PMT 2009] (a) 9.0 × 103 g (b) 8.1 × 104 g (c) 2.4 × 105 g (d) 1.3 × 104 g A current of strength 2.5 amp was passed through CuSO4 solution for 6 minutes 26 seconds. The amount of copper deposited is(Atomic weight of Cu = 63.5)(1 faraday = 96500 coulombs) [EAMCET 1989; MP PET 1994] (a) 0.3175 g (b) 3.175 g (c) 0.635 g (d) 6.35 g A certain quantity of electricity is passed through an aqueous solution of AgNO3 and cupric salt solution connected in series. The amount of Ag deposited is 1.08 gm, the amount of copper deposited is (atomic weight of Cu = 63.5; Ag = 108) [EAMCET 1986] (a) 0.6454 g (b) 6.354 g (c) 0.3177 g (d) 3.177 g The number of electrons required to deposit 1 gm atom of aluminium (at. wt. = 27) from a solution of aluminium chloride will be (where N is Avogadro’s number) [AIIMS 1992] (a) 1 N (b) 2 N (c) 3 N (d) 4 N The number of coulombs required to reduce 12.3 g of nitrobenzene to aniline [UPSEAT 2003] (a) 115800 C (b) 5790 C (c) 28950 C (d) 57900 C 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 [CPMT 1971] (a) 107.88 gm (b) 1.6 gm (c) 0.8 gm (d) 21.60 gm The amount of copper deposited by one Faraday current will be maximum in an acidic solution of one litre of [Kerala PMT 2006] (a) 1M Cu2Cl2 (b) 2M Cu (NO3)2 (c) 5M CuSO4 (d) 5M Cu3 (PO4)2 (e) 10M CuF2 The number of Faradays needed to reduce 4 gram equivalents of Cu++ to Cu metal will be [BHU 1981] (a) 1 (b) 2 (c) 1/2 (d) 4 Electrochemistry-Worksheet JEE Advance/AIIMS 290. 291. 292. 293. 294. 295. 296. 297. 33 On electrolysis, 1 mole of aluminium will be deposited from its molten salt by [MH CET 2000] (a) 3 moles of electron (b) 4 moles of electrons (c) 2 moles of electrons (d) 1 mole of electrons The atomic weight of Fe is 56. The weight of Fe deposited from FeCl3 solution by passing 0.6 Faraday of electricity is [MH CET 2000] (a) 5.6 g (b) 11.2 g (c) 22.4 g (d) 33.6 g If the aqueous solutions of the following salts are electrolysed for 1 hour with 10 ampere current, which solution will deposit the maximum mass of the metal at the cathode. The atomic weights are, Fe = 56, Zn = 65, Ag = 108, Hf = 178 and W = 184 [Kerala PMT 2006] (a) ZnSO4 (b) FeCl3 (c) HfCl4 (d) WCl6 (e) AgNO3 Silver is removed electrically from 200 ml of a 0.1 N solution of AgNO3 by a current of 0.1 ampere. How long will it take to remove half of the silver from the solution [AMU 1999] (a) 16 sec (b) 96.5 sec (c) 100 sec (d) 10 sec In order to separate oxygen from one mole of H2O the required quantity of coulomb would be [RPET 1999] 5 (a) 1.93 × 10 (b) 9.6 × 104 (c) 1.8 (d) 3.2 A current of 0.25A is passed through CuSO4 solution placed in voltameter for 45 minutes. The amount of Cu deposited on cathode is (At weight of Cu = 63.6) [BHU 2001] (a) 0.20 g (b) 0.22 g (c) 0.25 g (d) 0.30 g 4 g of copper was dissolved in concentrated nitric acid. The copper nitrate solution on strong heating gave 5 g of its oxide. The equivalent weight of copper is [KCET 2004] (a) 23 (b) 32 (c) 12 (d) 20 The amount of silver deposited by passing 241.25 coulomb of current through silver nitrate solution is [MH CET 2003] (a) 2.7 g (b) 2.7 mg (c) 0.27 g (d) 0.54 g Electrochemistry-Worksheet JEE Advance/AIIMS ELECTROCHEMISTRY ANSWERSHEET Que no. Ans. 1 c 2 b 3 b 4 a 5 d 6 c 7 d 8 a 9 c 10 b 11 b 12 a 13 c 14 d 15 d 16 a 17 a 18 d 19 c 20 c 21 b 22 b 23 a 24 b 25 c 26 a 27 b 28 a 29 d 30 a 31 b 32 a 33 b 34 a 35 a 36 a 37 c 34 Que no. Ans. Que no. Ans. Que no. Ans. Que no. Ans. Que no. Ans. Que no. Ans. Que no. Ans. 38 d 75 b 112 d 149 c 186 c 223 d 260 d 39 a 76 c 113 a 150 c 187 b 224 d 261 a 40 b 77 a 114 b 151 d 188 b 225 c 262 a 41 c 78 b 115 c 152 c 189 c 226 b 263 b 42 d 79 c 116 b 153 b 190 c 227 c 264 d 43 c 80 d 117 c 154 b 191 b 228 c 265 a 44 a 81 d 118 b 155 b 192 b 229 d 266 b 45 c 82 d 119 c 156 a 193 a 230 c 267 a 46 b 83 b 120 c 157 b 194 a 231 d 268 c 47 c 84 b 121 b 158 a 195 a 232 d 269 d 48 a 85 b 122 d 159 c 196 b 233 b 270 a 49 c 86 a 123 c 160 d 197 a 234 c 271 b 50 b 87 a 124 c 161 c 198 a 235 c 272 b 51 b 88 c 125 a 162 d 199 a 236 c 273 a 52 d 89 c 126 b 163 b 200 a 237 d 274 b 53 a 90 c 127 a 164 c 201 a 238 b 275 d 54 b 91 b 128 b 165 d 202 c 239 b 276 c 55 a 92 b 129 d 166 a 203 b 240 a 277 d 56 b 93 d 130 b 167 d 204 d 241 b 278 d 57 d 94 b 131 c 168 c 205 a 242 a 279 b 58 a 95 b 132 d 169 b 206 a 243 a 280 a 59 b 96 a 133 d 170 c 207 c 244 d 281 b 60 b 97 b 134 c 171 b 208 c 245 a 282 b 61 d 98 c 135 b 172 c 209 b 246 c 283 a 62 c 99 c 136 a 173 d 210 a 247 d 284 c 63 d 100 c 137 b 174 b 211 a 248 b 285 c 64 b 101 a 138 a 175 a 212 a 249 d 286 d 65 b 102 c 139 c 176 c 213 d 250 b 287 d 66 b 103 a 140 d 177 d 214 a 251 a 288 a 67 a 104 b 141 b 178 c 215 c 252 b 289 d 68 b 105 b 142 c 179 d 216 a 253 b 290 a 69 d 106 c 143 a 180 c 217 a 254 a 291 b 70 d 107 a 144 b 181 d 218 a 255 b 292 e 71 a 108 a 145 b 182 d 219 b 256 a 293 b 72 c 109 d 146 a 183 a 220 b 257 d 294 a 73 b 110 d 147 c 184 e 221 c 258 c 295 b 74 a 111 b 148 c 185 b 222 a 259 c 296 b 297 c Electrochemistry-Worksheet JEE Advance/AIIMS
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