Electrochemistry PYQs Set 2 (PDF)

Set 2 of 10 · Questions 31-60 of 293

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Mere Teacher · Previous Year Questions NEET Chemistry · Electrochemistry · Set 2 (Q31-60)
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31. $How many hours are required for a current of 3 A to decompose electrolytically one mole of water?$ (1) $9 hours$ (2) $12 hours$ (3) $18 hours$ (4) $24 hours$ 32. $In the Daniell cell, Zn (Zn^{2 +} ∥ Cu^{2 +}) Cu, when an external voltage is applied such that E_{external} > E_{cell}, current flows from______$ (1) $Zn to Cu$ (2) $Cu to Zn$ (3) $no current flows$ (4) $data insufficient$ 33. $On the basis of the following E^{o} values, the strongest oxidizing agent is [F e (C N)_{6}]^{4 -} \to [F e (C N)_{6}]^{3 -} + e^{-}; E^{o} = - 0.35 V F e^{2 +} \to F e^{3 +} + e^{-}; E^{o} = - 0.77 V$ (1) $F e^{3 +}$ (2) $[F e (C N)_{6}]^{3 -}$ (3) $[F e (C N)_{6}]^{4 -}$ (4) $F e^{2 +}$ 34. $For the electro chemical cell If E_{(M^{2 +} / M)}^{0} = 0.46 V and E_{(x / X^{2 -})}^{0} = 0.34 V . Which of the following is correct?$ (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) $M^{2 +} + X^{2 -} \to M + X is a spontaneous reaction$ 35. $The number of moles of electrons passed when current of 2 A is passed through a solution of electrofyte for 20 minutes is$ (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) $2.487 \times 10^{- 1} mol e^{-}$ 36. $In H_{2} = O_{2} fuel cell the reaction occurring at cathode is$ (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) $H^{+} + e^{-} ⟶ \frac{1}{2} H_{2}$ 37. $A conductivity cell containing 0.001 MAgNO_{3} solution develops resistance 6530 ohm at 25^{\circ} C . Calculate the electrical conductivity of solution at same temperature if the cell constant is 0.653 cm^{- 1} .$ (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) $1.0\times 1 0^{- 4} Ω-1 cm-1$ 38. $Calculate Δ G^{\circ} for the following cell reaction. [AP/2015] Zn (s) + Ag_{2} O (s) + H_{2} O (l) ⟶ Zn^{2 +} (aq) + 2 Ag (s) + 2^{-} OH (aq) E_{Ag^{+} / Ag}^{\circ} = + 0.80 V and E_{Zn^{2 +} / Zn}^{\circ} = - 0.76 V$ (1) $- 305 kJ / mol$ (2) $- 301 kJ / mol$ (3) $305 kJ / mol$ (4) $301 kJ / mol$ 39. $At 98 K, the conductivity of KCl solutions of molarity 0.1, 0.01 and 1.0 M are recorded as X, Y and Z, Scm^{- 1} respectively. The correct relation between X, Y and Z is$ (1) $X > Y > Z$ (2) $Z > X > Y$ (3) $Y > X > Z$ (4) $X > Z > Y$ 40. $The standard electrode potential for the half cell reactions are Zn^{2 +} + 2 e^{-} ⟶ Zn; E^{\circ} = - 0.76 V Fe^{2 +} + 2 e^{-} ⟶ Fe; E^{\circ} = - 0.44 V The e.m.f. of the cell reaction Fe^{2 +} + Zn ⟶ Zn^{2 +} + Fe is$ (1) $- 1.20 V$ (2) $+ 1.20 V$ (3) $+ 0.32 V$ (4) $- 0.32 V$ 41. $The products obtained at the cathode and anode respectively during the electrolysis of aqueous K_{2} SO_{4} solution using platinum electrodes are$ (1) $O_{2}, H_{2}$ (2) $H_{2}, O_{2}$ (3) $H_{2}, SO_{2}$ (4) $K, SO_{2}$ 42. $Given the equilibrium constant: K_{C} of the reaction: Cu (s) + 2 Ag^{+} (aq) \to Cu^{2 +} (aq) + 2 Ag (s) is 10 \times 10^{15} calculate the E_{cell}^{0} of this reaction at 298 K (2.303 \frac{RT}{F} at 298 K = 0.059 V)$ (1) $0.04736 mV$ (2) $0.4736 mV$ (3) $0.4736 V$ (4) $0.04736 V$ 43. $The pair of electrolytes that posses same value for the constant (A) in the Debye - Huckel On sagar equation, λ_{m} = λ_{m}^{\circ} - A C is$ (1) $NH_{4} Cl, NaBr$ (2) $NaCl, CaCl_{2}$ (3) $NaBr, MgSO_{4}$ (4) $MgSO_{4}, Na_{2} SO_{4}$ 44. $The highest electrical conductivity among the following aqueous solutions is of :$ (1) $0.1 M acetic acid$ (2) $0.1 M chloroacetic acid$ (3) $0.1 M fluoroacetic acid$ (4) $0.1 M difluoroacetic acid$ 45. $What will occur if a block of copper metal is dropped into a beaker containing a solution of 1M Z n S O_{4} ?$ (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) $No reaction will occur.$ 46. $What is the standard cell potential for the reaction with K = 1 (equilibrium constant)$ (1) $One$ (2) $Zero$ (3) $2.303$ (4) $Infinity$ 47. $Standard electrode potentials of three metals A, B and C are +0.5 V, -3.0 V and -1.2 V respectively. The reducing power of these metals is in the order :$ (1) $B > C > A$ (2) $A > B > C$ (3) $C > B > A$ (4) $A > C > B$ 48. $The anodic half-cell of lead-acid battery is recharged using electricity of 0.05 Faraday. The amount of P b S O_{4} electrolyzed in g during the process is: (Molar mass of P b S O_{4} = 303 g m o l^{-1})$ (1) $15.2$ (2) $22.8$ (3) $7.6$ (4) $11.6$ 49. $Identify the reaction from following having top position in EMF series (Std. red. potential) according to their electrode potential at 298 K .$ (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) $Mg^{2 +} + 2 e^{-} \to Mg (s)$ 50. $If an aqueous solution of NaF is electrolyzed between inert electrodes, the product obtained at anode is$ (1) $H_{2}$ (2) $Na$ (3) $O_{2}$ (4) $F_{2}$ 51. $A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A. The amount of the aluminium deposited at the cathode is [Given : molar mass of aluminium and chlorine are 27 g mol^{- 1} and 35.5 g mol^{- 1} respectively. Faraday constant (= 96500 Cmol^{- 1})$ (1) $1.660 g$ (2) $0.336 g$ (3) $0.441 g$ (4) $1.007 g$ 52. $Consider the statements S 1 and S 2 : S 1 : Conductivity always increases with decrease in the concentration of electrolyte. S 2 : Molar conductivity always increases with decrease in the concentration of electrolyte. The correct option among the following is:$ (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) $S 1 is correct and S 2 is wrong$ 53. $The gaseous products formed at cathode (X) and anode (Y), when an aqueous solution of sodium acetate is electrolysed are X Y$ (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) $C_{2} H_{6}, H_{2} CO_{2}$ 54. $For a closed circuit Daniell cell, which of the following plots is the accurate one at a given temperature?$ (1) (2) (3) (4) 55. $The standard electrode potential (M^{3 +} / M^{2 +}) for V, Cr, Mn & Co are -0.26 V, - 0,41 V, + 1.57 V and + 1.97 V, respectively. The metal ions which can liberate H_{2} from a dilute acid are$ (1) $V^{2 +} and M n^{2 +}$ (2) $Cr and CO$ (3) $V^{2 +} and C r^{2 +}$ (4) $M n^{2 +} and C o^{2 +}$ 56. $How many faradays of electricity are required to deposit 10 g of calcium from molten calcium chloride using inert electrodes? (molar mass of calcium = 40 g mol^{- 1})$ (1) $0.5 F$ (2) $1 F$ (3) $0.25 F$ (4) $2 F$ 57. $During the electrolysis of brine, by using inert electrodes,$ (1) $O_{2} liberates at anode$ (2) $H_{2} liberates at anode$ (3) $Na deposits on cathode$ (4) $Cl_{2} liberates at anode.$ 58. $The standard cell potential (E_{cell}^{⊖}) of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as 1.21 V. The standard half cell reduction potential for O_{2} (E_{O_{2} / H_{2} O}^{\circ}) is 1.229 V. Choose the correct statement:$ (1) $Reactants are fed at one go to each electrode.$ (2) $Oxygen is formed at the anode.$ (3) $The standard half cell reduction potential for the reduction of CO_{2} (E_{CO_{2} / CH_{3} OH}^{\circ}) is 19 mV$ (4) $Reduction of methanol takes place at the cathode.$ 59. $The charge required for the reduction of 1 mole of MnO_{4}^{-} to MnO_{2} is$ (1) $1 F$ (2) $3 F$ (3) $5 F$ (4) $7 F$ 60. $The standard Gibbs energy (Δ G^{0}) for the following reaction is A (s) + B^{2 +} (aq) \to A^{2 +} (aq) + B (s), K_{c} = 10^{12} at 25^{\circ} C (K_{c} =) equilibrium constant)$ (1) $- 150 kJ$ (2) $- 96.80 kJ$ (3) $- 68.47 kJ$ (4) $- 100 kJ$