Electrochemistry PYQs Set 5 (PDF)

Set 5 of 10 · Questions 121-150 of 293

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Mere Teacher · Previous Year Questions NEET Chemistry · Electrochemistry · Set 5 (Q121-150)
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121. $For a cell involving two electron changes, E_{cell} = 0.3 V at 25^{\circ} C . The equilibrium constant of the reaction is$ (1) $10^{- 10}$ (2) $3 \times 10^{- 2}$ (3) $10$ (4) $10^{10}$ 122. $The one which decreases with dilution is$ (1) $conductance$ (2) $specific conductance$ (3) $equivalent conductance$ (4) $molar conductance.$ 123. $Consider the following electrode processes of a cell, C l^{-} \to \frac{1}{2} C l_{2} + e^{-}, MCl + e^{-} \to M + C l^{-} If EMF of this cell is - 1.140 V and E^{\circ} value of the cell is - 0.55 V at 298 K, the value of the equilibrium constant of the sparingly soluble salt MCl is in the order of$ (1) $10^{- 10}$ (2) $10^{- 8}$ (3) $10^{- 7}$ (4) $10^{- 11}$ 124. $For Cr_{2} O_{7}^{2 -} + 14 H^{+} + 6 e^{-} \to 2 Cr^{3 +} + 7 H_{2} O, E^{\circ} = 1.33 V At (Cr_{2} O_{7}^{2 -}) = 4.5 millimole, (Cr^{3 +}) = 15 millimole, E is 1.067 V . The pH of the solution is nearly equal to$ (1) $2$ (2) $3$ (3) $5$ (4) $4$ 125. $In the electrolysis of aqueous sodium chloride solution, which of the half cell reaction will occur at anode?$ (1) $Cl_{(aq)}^{-} \to \frac{1}{2} Cl_{2} + e^{- m}; E_{cell}^{\circ} = 1.36 volts$ (2) $2 H_{2} O_{(n)} \to O_{2} + 4 H^{+} + 4 e^{-}; E_{cell}^{o} = 1.23 volts$ (3) $Na_{(aq)}^{+} + e^{-} ⟶ Na_{(s)}; E^{\circ} = - 2.71 volts$ (4) $H_{(aq)}^{+} + e ⟶ \frac{1}{2} H_{2}; E_{cell}^{\circ} = 0.00 volts$ 126. $The electric charge for electrode deposition of one equivalent of a substance is equal to$ (1) $1 A / s$ (2) $193000 coulombs$ (3) $\frac{96500}{( Atomic weight of the substance )}$ (4) $Charge on 1 mole of electrons$ 127. $Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R: Assertion A: In equation Δ_{r} G = - nF E_{cell}, value of Δ_{r} G depends on n . Reasons R: E_{cell} is an intensive property and Δ_{r} G is an extensive property. choose the correct answer from the options given below:$ (1) $A is false but R is true.$ (2) $Both A and R are true and R is the correct explanation of A .$ (3) $Both A and R are true but R is NOT the correct explanation of A .$ (4) $A is true but R is false$ 128. $If the E_{cell}^{\circ} of an equilibrium reaction A (s) + 2 B^{2 +} (aq) ⟶ A^{2 +} (aq) + 2 B (s) at 298 K is 0.59 V, the equilibrium constant K_{c} is$ (1) $1.0 \times 10^{10}$ (2) $1.0 \times 10^{2}$ (3) $1.0 \times 10^{- 20}$ (4) $1.0 \times 10^{20}$ 129. $When the same quantity of electricity is passed through the aqueous solutions of the given electrolytes for the same amount of time, which metal will be deposited in maximum amount on the cathode?$ (1) $ZnSO_{4}$ (2) $FeCl_{3}$ (3) $AgNO_{3}$ (4) $NiCl_{2}$ 130. $Which of the following acts as oxidising agent in hydrogen-oxygen fuel cell?$ (1) $H_{2}$ (2) $O_{2}$ (3) $KOH$ (4) $C$ 131. $At 2 5^{0} C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 o h m^{- 1} c m^{2} m o l^{- 1} and at infinite dilution its molar conductance is 238 o h m^{- 1} c m^{2} m o l^{- 1} . The degree of ionisation of ammonium hydroxide at the same concentration and temperature is$ (1) $4.008%$ (2) $40.800%$ (3) $2.080%$ (4) $20.800%$ 132. $For a cell involving one electron E^{\circ} cell = 0.59 V at 298 K , the equilibrium constant for the cell reaction is (Given that) \frac{2.303 RT}{F} = 0.059 V at (T = 298 K)$ (1) $1.0 \times 10^{2}$ (2) $1.0 \times 10^{5}$ (3) $1.0 \times 10^{10}$ (4) $1.0 \times 10^{30}$ 133. $The molar conductivity of 0.007 M acetic acid is 20 S cm^{2} mol^{- 1} . What is the dissociation constant of acetic acid? Choose the correct option. (Λ_{H^{+}}^{\circ} = 350 S cm^{2} mol^{- 1} Λ_{CH_{3} COO^{-}}^{\circ} = 50 S cm^{2} mol^{- 1})$ (1) $2.50 \times 10^{- 4} mol L^{- 1}$ (2) $1.75 \times 10^{- 5} mol L^{- 1}$ (3) $2.50 \times 10^{- 5} mol L^{- 1}$ (4) $1.75 \times 10^{- 4} mol L^{- 1}$ 134. $The molar conductance of NaCl, HCl and CH_{3} COONa at infinite dilution are 126.45, 426.16 and 91.0 S cm^{2} mol^{- 1} respectively. The molar conductance of CH_{3} COOH at infinite dilution is. Choose the right option for your answer.$ (1) $390.71 S cm^{2} mol^{- 1}$ (2) $698.28 S cm^{2} mol^{- 1}$ (3) $540.48 S cm^{2} mol^{- 1}$ (4) $201.28 S cm^{2} mol^{- 1}$ 135. $For a strong electrolyte, a plot of molar conductivity against (concentration) 1/2 is a straight line, with a negative slope, the correct unit for the slope is$ (1) $Scm^{2} mol^{- 3/2} L^{- 1/2}$ (2) $Sc m^{2} mo l^{- 3/2} L^{1/2}$ (3) $Scm^{2} mol^{- 3/2} L$ (4) $Scm^{2} mol^{- 1} L^{1/2}$ 136. $Correct order of limiting molar conductivity for cations in water at 298 K is:$ (1) $H^{+} > Na^{+} > K^{+} > Ca^{2 +} > Mg^{2 +}$ (2) $H^{+} > Ca^{2 +} > Mg^{2 +} > K^{+} > Na^{+}$ (3) $Mg^{2 +} > H^{+} > Ca^{2 +} > K^{+} > Na^{+}$ (4) $H^{+} > Na^{+} > Ca^{2 +} > Mg^{2 +} > K^{+}$ 137. $Two Faraday of electricity is passed through a solution of C u S O_{4} . The mass of copper deposited at the cathode is : (at. mass of Cu = 63.5 amu)$ (1) $0 g$ (2) $63.5 g$ (3) $2 g$ (4) $127 g$ 138. $What is the molar conductivity of CH_{3} CO_{2} H at infinite dilution? Given that, \land_{m}^{\circ} (CH_{3} CO_{2})_{2} Ba = x_{1} S cm^{2} mol^{- 1} \land_{m}^{\circ} (BaCl_{2}) = x_{2} S cm^{2} mol^{- 1} \land_{m}^{o} (HCl) = x_{3} S cm^{2} mol^{- 1}$ (1) $\frac{x _{1} - x _{2}}{2} + x_{3}$ (2) $\frac{x _{1} - x _{3}}{2} + x_{2}$ (3) $\frac{x _{2} - x _{3}}{2} + x_{1}$ (4) $x_{1} + x_{3} - x_{2}$ 139. $The overall reaction taking place at anode during electrolysis of fused sodium chloride using suitable electrode is$ (1) $oxidation of chloride$ (2) $reduction of sodium ions$ (3) $reduction of chlorine$ (4) $oxidation of sodium atoms.$ 140. $The electrode potential for M^{2 +} (aq) + e^{-} ⟶ M^{+} (aq) M^{+} (aq) + e^{-} ⟶ M (s) are + 0.15 V and + 0.50 V respectively. The value of E^{\circ}_{M^{2 +} / M} will be$ (1) $0.150 V$ (2) $0.300 V$ (3) $0.325 V$ (4) $0.650 V$ 141. $The conductivity of centimolar solution of KCl at 25^{\circ} C is 0.0210 ohm^{- 1} cm^{- 1} and the. resistance of the cell containing the solution at 25^{\circ} C is 60 ohm . The value of cell constant is:$ (1) $3.34 cm^{- 1}$ (2) $3.28 cm^{- 1}$ (3) $1.34 cm^{- 1}$ (4) $1.26 cm^{- 1}$ 142. $Given below are two statements: Statement (I): Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode. Statement (II): The rate of corrosion is more in alkaline medium than in acidic medium. choose the correct answer from the options given below:$ (1) $Both Statement I and Statement II are true$ (2) $Statement I is false but Statement II is true$ (3) $Statement I is true but Statement II is false$ (4) $Both Statement I and Statement II are false$ 143. $Match List - I with List - II: List - I Applications (A) Transistors (B) Hearing aids (C) Invertors (D) Apollo space ship List - II Batteries/Cell (I) Anode - Zn / Hg; Cathode - HgO + C (II) Hydrogen fuel cell (III) Anode - Zn; Cathode - Carbon (IV) Anode -Pb; Cathode - Pb ∣ PbO_{2} Choose the correct answer from the options given below :$ (1) $(A)-(III), (B)-(II), (C)-(IV), (D)-(I)$ (2) $(A)-(II), (B)-(III), (C)-(IV), (D)-(I)$ (3) $(A)-(III), (B)-(I), (C)-(IV), (D)-(II)$ (4) $(A)-(IV), (B)-(III), (C)-(II), (D)-(I)$ 144. $When a current of 10 A is passes through molten AlCl_{3} for 1.608 minutes. The mass of Al deposited will be [Atomic mass of Al = 27 g]$ (1) $0.09 g$ (2) $0.81 g$ (3) $1.35 g$ (4) $0.27 g$ 145. $Consider the following electrodes: P = Zn^{2 +} (0.0001 M) / Zn; Q = Zn^{2 +} (0.1 M) / Zn; R = Zn^{2 +} (0.01 M) / Zn; S = Zn^{2 +} (0.001 M) / Zn E_{Zn / Zn^{2 +}}^{\circ} = - 0.76 V electrode potentials of the above electrode in volts are in the order$ (1) $P > S > R > Q$ (2) $Q > R > S > P$ (3) $S > R > Q > P$ (4) $P > Q > R > S$ 146. $Which from following expressions is used to find the cell potential of Cd_{(s)} (Cd_{(aq)}^{++}) / Cu_{(aq)}^{++} ∣ Cu_{(s)} cell at 25^{\circ} C ?$ (1) $E_{cell} = E_{cell}^{\circ} - 0.0296 log \frac{( Cd ^{++} )}{( Cu ^{++} )}$ (2) $E_{cell} = E_{cell}^{\circ} + 0.0296 log \frac{( Cd ^{++} )}{( Cu ^{++} )}$ (3) $E_{cell} = E_{cell}^{\circ} - 0.0592 log \frac{( Cu ^{++} )}{( Cd ^{++} )}$ (4) $E_{cell} = E_{cell}^{\circ} + 0.0592 log \frac{( Cu ^{++} )}{( Cd ^{++} )}$ 147. $Calculate Δ G^{\circ} for the cell Sn_{(s)} (Sn^{++} (1 M) ∥ Ag^{+} (1 M)) Ag_{(s)} at 25^{\circ} C (E_{cell}^{\circ} = 0.90 V) .$ (1) $- 173.7 kJ$ (2) $- 225.3 kJ$ (3) $- 100.2 kJ$ (4) $- 290.8 kJ$ 148. $One litre solution of MgCl_{2} is electrolyzed completely by passing a current of 1 A for 16 min 5 sec . The original concentration of MgCl_{2} solution was (Atomic mass of Mg = 24)$ (1) $5 \times 10^{- 3} M$ (2) $5 \times 10^{- 2} M$ (3) $0.5\times 1 0^{- 3} M$ (4) $1.0 \times 10^{- 2} M$ 149. $Resistance of a conductivity cell filled with 0.1 mol L^{- 1} NaCl is 100 ohm . If the resistance of the same cell when filled with 0.02 mol L^{- 1} NaCl solution is 258 ohm, the conductivity of 0.02 mol L^{- 1} NaCl solution is (Conductivity of 0.1 mol L^{- 1} NaCl is 1.29 S m^{- 1})$ (1) $1.0 S m^{- 1}$ (2) $0.2 S m^{- 1}$ (3) $2.0 S m^{- 1}$ (4) $0.5 S m^{- 1}$ 150. $Standard electrode potentials of three metals X, Y and Z are - 1.2 V, + 0.5 V and—3.0 V respectively. The reducing power of these metals will be$ (1) $Y > Z > X$ (2) $Y > X > Z$ (3) $Z > X > Y$ (4) $X > Y > Z$