Electrochemistry PYQs Set 4 (PDF)

Set 4 of 10 · Questions 91-120 of 293

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Mere Teacher · Previous Year Questions NEET Chemistry · Electrochemistry · Set 4 (Q91-120)
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91. $Given: Co^{3 +} + e^{-} \to Co^{2 +}; E^{0} = + 1.81 V Pb^{4 +} + 2 e^{-} \to Pb^{2 +}; E^{o} = + 1.67 V Ce^{4 +} + e^{-} \to Ce^{3 +}; E^{\circ} = + 1.61 V Bi^{3 +} + 3 e^{-} \to Bi; E^{\circ} = + 0.20 V oxidizing power of the species will increase in the order:$ (1) $Ce^{4 +} < Pb^{4 +} < Bi^{3 +} < Co^{3 +}$ (2) $Bi^{3 +} < Ce^{4 +} < Pb^{4 +} < Co^{3 +}$ (3) $Co^{3 +} < Ce^{4 +} < Bi^{3 +} < Pb^{4 +}$ (4) $Co^{3 +} < Pb^{4 +} < Ce^{4 +} < Bi^{3 +}$ 92. $The time required (in hours) to reduce 3 mol of Fe^{3 +} ions to Fe^{2 +} ions with 2.0 amperes of current is (1 F (= 96500 C mol^{- 1})$ (1) $30.2$ (2) $40.2$ (3) $10.2$ (4) $15.2$ 93. $The variation of λ_{m} of acetic acid with concentration is correctly represented as$ (1) (2) (3) (4) 94. $For the cell reaction 2 Fe^{3 +} (aq) + 2 I^{-} (aq) \to 2 Fe^{2 +} (aq) + I_{2} (aq) E_{cell}^{Θ} = 0.24 V at 298 K . The standard Gibbs energy (Δ_{r} G^{⊖}) of the cell reaction is [Given that Faraday constant F = 96500 C mol^{- 1}]$ (1) $-46.32 kJ mol^{- 1}$ (2) $-23.16 kJ mol^{- 1}$ (3) $46.32 kJ mol^{- 1}$ (4) $23.16 kJ mol^{- 1}$ 95. $Calculate current in ampere required to deposit 4.8 g Cu from its salt solution in 30 minutes. (Molar mass of Cu = 63.5 g mol^{- 1})$ (1) $8.1 ampere$ (2) $6.4 ampere$ (3) $10.5 ampere$ (4) $12.3 ampere$ 96. $The reduction potential of a half cell consisting of a Pt electrode immersed in 2.0 M Fe^{2 +} and 0.02 M Fe^{3 +} solution (in V) is Given (\frac{2.303 RT}{F} = 0.059, E_{Fe^{3 +} ∣ Fe^{2 +}}^{0} = 0.771 V)$ (1) $0.543$ (2) $0.653$ (3) $0.733$ (4) $0.822$ 97. $The reduction potential of hydrogen electrode at 25^{\circ} C in a neutral solution is (p_{H_{2}} = 1) bar)$ (1) $0.059 V$ (2) $- 0.059 V$ (3) $- 0.413 V$ (4) $0.0 V$ 98. $Find the observed EMF of the cell Cd ∣ Cd^{2 +} (0.01 M) ∥ Cu^{2 +} (0.01 M) ∣ Cu under conditions, internal resistance of 4Ω and producing a current of 0.15 A . (Given, E_{Cu^{2 +} / Cu}^{\circ} = 0.35 V and E^{\circ} Cd^{2 +} / Cd = - 0.4 V)$ (1) $0.75 V$ (2) $0.15 V$ (3) $0.6 V$ (4) $0.9 V$ 99. $For hydrogen - oxygen fuel cell at one atm and 298 K H_{2 (g)} + \frac{1}{2} O_{2 (g)} \to H_{2} O_{(l)}; Δ G^{\circ} = - 240 kJ E^{\circ} for the cell is approximately, (Given : F = 96, 500 C)$ (1) $2.48 V$ (2) $1.24 V$ (3) $2.5 V$ (4) $1.26 V$ 100. $Given E_{Fe^{+ 3} / Fe^{+ 2}}^{0} = + 0.76 V and E_{I_{2} / I^{-}}^{0} = + 0.55 V . The equilibrium constant for the reaction taking place in galvanic cell consisting of above two electrodes is (\frac{2.303 RT}{F} = 0.06)$ (1) $1 \times 10^{9}$ (2) $3 \times 10^{8}$ (3) $5 \times 10^{12}$ (4) $1 \times 10^{7}$ 101. $38.6 amperes of current is passed for 100 seconds through an aqueous CuSO_{4} solution using platinum electrodes. The mass of copper consumed from the solution and volume of gas liberated at STP are respectively (molar mass of (Cu = 63.54 g mol^{- 1}) .$ (1) $6.37 g, 0.448 L$ (2) $0.63 g, 0.224 L$ (3) $1.27 g, 0.224 L$ (4) $4 g, 0.448 L$ 102. $The product, which is not obtained during the electrolysis of brine solution is$ (1) $H_{2}$ (2) $HC1$ (3) $NaOH$ (4) $C 1_{2}$ 103. $What is the conductivity of 0.05 M BaCl_{2} solution if its molar conductivity is 220 Ω^{- 1} cm^{2} mol^{- 1} ?$ (1) $0.011 Ω^{- 1} cm^{- 1}$ (2) $0.033 Ω^{- 1} cm^{- 1}$ (3) $0.022 Ω^{- 1} cm^{- 1}$ (4) $0.044 Ω^{- 1} cm^{- 1}$ 104. $Calculate E_{cell}^{o} for Cd_{(s)} (Cd^{++} (1 M) ∥ Ag^{+} (1 M)) Ag_{(s)} (E_{Cd}^{o} = - 0.403 V; E_{Ag}^{o} = 0.799 V)$ (1) $1.202 V$ (2) $- 1.202 V$ (3) $0.396 V$ (4) $- 0.396 V$ 105. $If hydrogen electrodes dipped in two solutions of pH = 3 and pH = 6 are connected by a salt bridge, the emf of the resulting cell is$ (1) $0.177 V$ (2) $0.3 V$ (3) $0.052 V$ (4) $0.104 V$ 106. $Which of the following cannot be considered as application of electrochemical series?$ (1) $Relative strength of reducing agent$ (2) $Use of SHE in automobile battery$ (3) $Relative strength of oxidising agent$ (4) $Spontaneity of redox reaction$ 107. $Resistance of 0.2 M solution of an electrolyte is 50 Ω. The specific conductance of the solution is 1.4 S m^{-1} . The resistance of 0.5 M solution of the same electrolyte is 280 Ω. The molar conductivity of 0.5 M solution of the electrolyte in S m^{2} m o l^{-1} is :$ (1) $5 \times 1 0^{- 4}$ (2) $5 \times 1 0^{- 3}$ (3) $5 \times 103$ (4) $5 \times 102$ 108. $For spontaneity of a cell, which is correct?$ (1) $Δ G = + ve, Δ E = + ve$ (2) $Δ G = - ve$ (3) $Δ G = 0, Δ E = 0$ (4) $Δ G = - ve, Δ E = 0$ 109. $The reaction at cathode in the cells commonly used in clocks involves.$ (1) $reduction of Mn from +7 to +2$ (2) $reduction of Mn from +4 to +3$ (3) $oxidation of Mn from +3 to +4$ (4) $oxidation of Mn from +2 to +7$ 110. $Consider the following relations for emf of an electrochemical cell(i) EMF of cell = (Oxidation potential of anode) ‐(Reduction potential of cathode)(ii) EMF of cell = (Oxidation potential of anode) + ( Reduction potential of cathode)(iii) EMF of cell = (Reductional potential of anode) + (Reduction potential of cathode) (iv) EMF of cell = (Oxidation potential of anode) ‐(Oxidation potential of cathode)Which of the above relations are correct?$ (1) $(iii) and (i)$ (2) $(i) and (ii)$ (3) $(iii) and (iv)$ (4) $(ii) and (iv)$ 111. $Salts of A (atomic weight 8 ), B (atomic weight 18 ) and C (atomic weight 50 ) were electrolysed under identical conditions using the same quantity of electricity. It was found that 2.4 g of A was deposited, the weight of B and C deposited are 1.8 g and 7.5 g, respectively. The valences of A, B and C are, respectively,$ (1) $3,1 and 2$ (2) $1,2 and 3$ (3) $1,3 and 2$ (4) $3,2 and 1$ 112. $The molar conductivities Λ_{NaOAc}^{0} and Λ_{HCl}^{0} at infinite dilution in water at 25°C are 91.0 and 426.2 Scm^{2} /mol respectively. To calculate Λ_{HOAc}^{0}, the additional value required is :$ (1) $Λ_{H_{2} O}^{0}$ (2) $Λ_{KCl}^{0}$ (3) $Λ_{NaOH}^{0}$ (4) $Λ_{NaCl}^{0}$ 113. $Identify the gas produced due to reduction of NH_{4}^{+} ions at cathode during working of dry cell.$ (1) $Ammonia$ (2) $Hydrogen$ (3) $Hydrogen chloride$ (4) $Chlorine$ 114. $The resistance of 0.1 M weak acid HA in a conductivitycellis 2 \times 10^{3} ohm . Thecellconstant of the cell is 0.78 C m^{- 1} and λ^{6}_{m} of acid H A is 390 S cm^{2} mol^{- 1} . The pH of the solution is$ (1) $3.3$ (2) $4.2$ (3) $5$ (4) $3$ 115. $A solution of Ni (NO_{3})_{2} is electrolysed between platinum electrodes using 0.1 Faraday electricity. How many mode of Ni will be deposited at the cathode?$ (1) $0.05$ (2) $0.20$ (3) $0.15$ (4) $0.10$ 116. $Which of the following does not conduct electricity?$ (1) $Fused NaCl$ (2) $Solid NaCl$ (3) $Brine solution$ (4) $Copper$ 117. $How can an electrochemical cell be converted into an electrolytic cell?$ (1) $Applying an external opposite potential lower than E^{0} cell.$ (2) $Reversing the flow of ions in salt bridge.$ (3) $Applying an external opposite potential greater than E^{0} cell-$ (4) $Exchanging the electrodes at anode and cathode.$ 118. $The amount of current in faraday, required for the reduction of 1 mol of Cr_{2} O_{7}^{2 -} ions to Cr^{3 +} is$ (1) $1 F$ (2) $2 F$ (3) $6 F$ (4) $4 F$ 119. $For a cell given below: Ag (Ag^{+}) (Cu^{2 +}) Cu Ag^{+} - + e^{-} \to A + g E^{\circ} = x C u^{2 +} + 2 e^{-} \to, E^{\circ} = y E^{\circ} cell is:$ (1) $x + 2y$ (2) $2x + y$ (3) $y -x$ (4) $y - 2x$ 120. $The molar conductivity of 0.027 M methanoic acid is 40.42 Scm^{2} mol^{- 1} . The value of dissociation constant of this acid is (Given λ_{H^{+}}^{\circ} = 349.6 S cm^{2} mol^{- 1} and λ_{HCOO^{-}}^{\circ} = 54.6 S (cm^{2} mol^{- 1})$ (1) $1.5 \times 10^{- 5}$ (2) $6.0 \times 10^{- 5}$ (3) $4.5 \times 10^{- 4}$ (4) $3.0 \times 10^{- 4}$