Electrochemistry PYQs Set 2 (PDF)

Set 2 of 13 · Questions 31-60 of 363

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Electrochemistry · Set 2 (Q31-60)
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31. $The metals that are employed in the battery industries are A. Fe B. Mn C. Ni D. Cr E. Cd Choose the correct answer from the options given below:$ (1) $B, C and E only$ (2) $A, B, C, D and E$ (3) $A, B, C and D only$ (4) $B, D and E only$ 32. $The efficiency of a fuel cell is given by$ (1) $Δ G /Δ S$ (2) $Δ G /Δ H$ (3) $Δ S /Δ G$ (4) $Δ H /Δ G$ 33. $How many hours are required for a current of 3 A to decompose electrolytically one mole of water?$ (1) $9 hours$ (2) $12 hours$ (3) $18 hours$ (4) $24 hours$ 34. $In the Daniell cell, Zn (Zn^{2 +} ∥ Cu^{2 +}) Cu, when an external voltage is applied such that E_{external} > E_{cell}, current flows from______$ (1) $Zn to Cu$ (2) $Cu to Zn$ (3) $no current flows$ (4) $data insufficient$ 35. $On the basis of the following E^{o} values, the strongest oxidizing agent is [F e (C N)_{6}]^{4 -} \to [F e (C N)_{6}]^{3 -} + e^{-}; E^{o} = - 0.35 V F e^{2 +} \to F e^{3 +} + e^{-}; E^{o} = - 0.77 V$ (1) $F e^{3 +}$ (2) $[F e (C N)_{6}]^{3 -}$ (3) $[F e (C N)_{6}]^{4 -}$ (4) $F e^{2 +}$ 36. $For the electro chemical cell If E_{(M^{2 +} / M)}^{0} = 0.46 V and E_{(x / X^{2 -})}^{0} = 0.34 V . Which of the following is correct?$ (1) $M + X \to M^{2 +} + X^{2 -} is a spontaneous reaction$ (2) $E_{cell} = 0.80 V$ (3) $E_{cell} = - 0.80 V$ (4) $M^{2 +} + X^{2 -} \to M + X is a spontaneous reaction$ 37. $The number of moles of electrons passed when current of 2 A is passed through a solution of electrofyte for 20 minutes is$ (1) $4.1 \times 10^{- 4} mol e^{-}$ (2) $1.24 \times 10^{- 2} mol e^{-}$ (3) $2.487 \times 10^{- 2} mol e^{-}$ (4) $2.487 \times 10^{- 1} mol e^{-}$ 38. $In H_{2} = O_{2} fuel cell the reaction occurring at cathode is$ (1) $O_{2} (g) + 2 H_{2} O (l) + 4 e^{-} ⟶ 4 O H^{-} (a q .)$ (2) $H_{(aq)}^{+} + OH_{(aq)}^{-} \to H_{2} O_{(i)}$ (3) $2 H_{2 (g)} + O_{2 (g)} ⟶ 2 H_{2} O_{(l)}$ (4) $H^{+} + e^{-} ⟶ \frac{1}{2} H_{2}$ 39. $A conductivity cell containing 0.001 MAgNO_{3} solution develops resistance 6530 ohm at 25^{\circ} C . Calculate the electrical conductivity of solution at same temperature if the cell constant is 0.653 cm^{- 1} .$ (1) $1.3\times 1 0^{- 4} Ω-1 cm-1$ (2) $1.5\times 1 0^{- 4} Ω-1 cm-1$ (3) $1.7\times 1 0^{- 4} Ω-1 cm-1$ (4) $1.0\times 1 0^{- 4} Ω-1 cm-1$ 40. $Calculate Δ G^{\circ} for the following cell reaction. [AP/2015] Zn (s) + Ag_{2} O (s) + H_{2} O (l) ⟶ Zn^{2 +} (aq) + 2 Ag (s) + 2^{-} OH (aq) E_{Ag^{+} / Ag}^{\circ} = + 0.80 V and E_{Zn^{2 +} / Zn}^{\circ} = - 0.76 V$ (1) $- 305 kJ / mol$ (2) $- 301 kJ / mol$ (3) $305 kJ / mol$ (4) $301 kJ / mol$ 41. $At 98 K, the conductivity of KCl solutions of molarity 0.1, 0.01 and 1.0 M are recorded as X, Y and Z, Scm^{- 1} respectively. The correct relation between X, Y and Z is$ (1) $X > Y > Z$ (2) $Z > X > Y$ (3) $Y > X > Z$ (4) $X > Z > Y$ 42. $The standard electrode potential for the half cell reactions are Zn^{2 +} + 2 e^{-} ⟶ Zn; E^{\circ} = - 0.76 V Fe^{2 +} + 2 e^{-} ⟶ Fe; E^{\circ} = - 0.44 V The e.m.f. of the cell reaction Fe^{2 +} + Zn ⟶ Zn^{2 +} + Fe is$ (1) $- 1.20 V$ (2) $+ 1.20 V$ (3) $+ 0.32 V$ (4) $- 0.32 V$ 43. $The products obtained at the cathode and anode respectively during the electrolysis of aqueous K_{2} SO_{4} solution using platinum electrodes are$ (1) $O_{2}, H_{2}$ (2) $H_{2}, O_{2}$ (3) $H_{2}, SO_{2}$ (4) $K, SO_{2}$ 44. $Given the equilibrium constant: K_{C} of the reaction: Cu (s) + 2 Ag^{+} (aq) \to Cu^{2 +} (aq) + 2 Ag (s) is 10 \times 10^{15} calculate the E_{cell}^{0} of this reaction at 298 K (2.303 \frac{RT}{F} at 298 K = 0.059 V)$ (1) $0.04736 mV$ (2) $0.4736 mV$ (3) $0.4736 V$ (4) $0.04736 V$ 45. $The pair of electrolytes that posses same value for the constant (A) in the Debye - Huckel On sagar equation, λ_{m} = λ_{m}^{\circ} - A C is$ (1) $NH_{4} Cl, NaBr$ (2) $NaCl, CaCl_{2}$ (3) $NaBr, MgSO_{4}$ (4) $MgSO_{4}, Na_{2} SO_{4}$ 46. $The highest electrical conductivity among the following aqueous solutions is of :$ (1) $0.1 M acetic acid$ (2) $0.1 M chloroacetic acid$ (3) $0.1 M fluoroacetic acid$ (4) $0.1 M difluoroacetic acid$ 47. $What will occur if a block of copper metal is dropped into a beaker containing a solution of 1M Z n S O_{4} ?$ (1) $The copper metal will dissolve and zinc metal will be deposited.$ (2) $The copper metal will dissolve with evolution of oxygen gas.$ (3) $The copper metal will dissolve with evolution of hydrogen gas.$ (4) $No reaction will occur.$ 48. $What is the standard cell potential for the reaction with K = 1 (equilibrium constant)$ (1) $One$ (2) $Zero$ (3) $2.303$ (4) $Infinity$ 49. $Standard electrode potentials of three metals A, B and C are +0.5 V, -3.0 V and -1.2 V respectively. The reducing power of these metals is in the order :$ (1) $B > C > A$ (2) $A > B > C$ (3) $C > B > A$ (4) $A > C > B$ 50. $The anodic half-cell of lead-acid battery is recharged using electricity of 0.05 Faraday. The amount of P b S O_{4} electrolyzed in g during the process is: (Molar mass of P b S O_{4} = 303 g m o l^{-1})$ (1) $15.2$ (2) $22.8$ (3) $7.6$ (4) $11.6$ 51. $Identify the reaction from following having top position in EMF series (Std. red. potential) according to their electrode potential at 298 K .$ (1) $F e^{2 +} + 2 e^{-} \to F e (s)$ (2) $A u^{3 +} + 3 e^{-} \to A u (s)$ (3) $K^{+} + 1 e^{-} \to K (s)$ (4) $Mg^{2 +} + 2 e^{-} \to Mg (s)$ 52. $If an aqueous solution of NaF is electrolyzed between inert electrodes, the product obtained at anode is$ (1) $H_{2}$ (2) $Na$ (3) $O_{2}$ (4) $F_{2}$ 53. $A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A. The amount of the aluminium deposited at the cathode is [Given : molar mass of aluminium and chlorine are 27 g mol^{- 1} and 35.5 g mol^{- 1} respectively. Faraday constant (= 96500 Cmol^{- 1})$ (1) $1.660 g$ (2) $0.336 g$ (3) $0.441 g$ (4) $1.007 g$ 54. $Consider the statements S 1 and S 2 : S 1 : Conductivity always increases with decrease in the concentration of electrolyte. S 2 : Molar conductivity always increases with decrease in the concentration of electrolyte. The correct option among the following is:$ (1) $Both S 1 and S 2 are wrong$ (2) $S 1 is wrong and S 2 is correct$ (3) $Both S 1 and S 2 are correct$ (4) $S 1 is correct and S 2 is wrong$ 55. $The gaseous products formed at cathode (X) and anode (Y), when an aqueous solution of sodium acetate is electrolysed are X Y$ (1) $CO_{2} C_{2} H_{6}, H_{2}$ (2) $H_{2}, CO_{2} C_{2} H_{6}$ (3) $H_{2} C_{2} H_{6}, CO_{2}$ (4) $C_{2} H_{6}, H_{2} CO_{2}$ 56. $The resistivity of a 0.8 M solution of an electrolyte is 5x10^{- 3} Ω cm. Its molar conductivity is _______x 1 0^{4} Ω^{- 1} c m^{2} m o l^{- 1} . (Nearest integer)$ 57. $The mass of silver (Molar mass of Ag : 108 gmol^{- 1}) displaced by a quantity of electricity which displaces 5600 mL of O_{2} at S.T.P. will be______ g.$ 58. $The values of conductivity of some materials at 298.15 K in Sm^{- 1} are 2.1 \times 10^{3}, 1.0 \times 10^{- 16}, 1.2 \times 10, 3.91, 1.5 \times 10^{- 2}, 1 \times 10^{- 7}, 1.0 \times 10^{3} . The number of conductors among the materials is_______$ 59. $The hydrogen electrode is dipped in a solution of pH = 3 at 25^{\circ} C . The potential of the electrode will be _______\times 10^{- 2} V (\frac{2.303 RT}{F} = 0.059 V)$ 60. $A 5.0 m moldm^{- 3} aqueous solution of KCl has a conductance of 0.55 mS when measured in a cell constant 1.3 cm^{- 1} The molar conductivity of this solution is mSm^{2} mol^{- 1} (Round off to the Nearest Integer)$