Electrochemistry PYQs Set 7 (PDF)

Set 7 of 13 · Questions 181-210 of 363

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Electrochemistry · Set 7 (Q181-210)
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181. $Λ º_{m} for NaCl, HCl and NaA are 126.4, 425.9 and 100.5 S c m^{2} m o l^{-1}, respectively. If the conductivity of 0.001 M HA is 5 \times 1 0^{-5} S c m^{-1}, degree of dissociation of HA is:$ (1) $0.125$ (2) $0.50$ (3) $0.75$ (4) $0.25$ 182. $Which of the following ions does not liberate hydrogen gas on reaction with dilute acids?$ (1) $M n^{2 +}$ (2) $T i^{2 +}$ (3) $V^{2 +}$ (4) $C r^{2 +}$ 183. $H_{2 (g)} + 2 AgCl_{(s)} ⇌ 2 Ag_{(s)} + 2 HCl_{(aq)} E_{cell}^{\circ} at 25^{\circ} C for the cell is 0.22 V . The equilibrium constant at 25^{\circ} C is$ (1) $2.8 \times 10^{7}$ (2) $5.2 \times 10^{8}$ (3) $2.8 \times 10^{5}$ (4) $5.2 \times 10^{4}$ 184. $During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is$ (1) $55 minutes$ (2) $110 minutes$ (3) $220 minutes$ (4) $330 minutes.$ 185. $At 300 K, the conductivity of 0.01 mol dm^{- 3} aqueous solution of acetic acid is 19.5 \times 10^{- 5} mho cm^{- 1} and limiting molar conductivity of acetic acid at the same temperature is 390 mho cm^{2} mol^{- 1} . The degree dissociation of acetic acid is$ (1) $5.0 \times 10^{- 5}$ (2) $5.0 \times 10^{- 2}$ (3) $2.5 \times 10^{- 5}$ (4) $7.5 \times 10^{- 2}$ 186. $At a particular temperature, the ratio of molar conductance to specific conductance of 0.01 M NaCl solution is$ (1) $10^{5} cm^{3} mol^{- 1}$ (2) $10^{3} cm^{3} mol^{- 1}$ (3) $10 cm^{3} mol^{- 1}$ (4) $10^{5} cm^{2} mol^{- 1}$ 187. $The emf of a galvanic cell constituted with the electrodes Zn^{2 +} ∣ Zn (- 0.76 V) and Fe^{2 +} ∣ Fe (- 0.41 V) is$ (1) $- 0.35 V$ (2) $+ 1.17 V$ (3) $+ 0.35 V$ (4) $- 1.17 V$ 188. $Consider the following standard electrode potentials (Eº in volts) in aqueous solution: Element M^{3 +} / M M^{+} / M Al -1.66 + 0.55 Tl +1.26 - 0.34 Based on these data, which of the following statements is correct?$ (1) $A l^{+} is more stable than A l^{3 +}$ (2) $T l^{3 +} is more stable than A l^{3 +}$ (3) $T l^{+} is more stable than A l^{3 +}$ (4) $T l^{+} is more stable than A l^{+}$ 189. $For the given cell; Cu (s) (C u^{2 +} (C_{1} M)) (C u^{2 +} (C_{2} M)) Cu (s) change in Gibbs energy (∆ G) is negative, if$ (1) $C_{2} = 2 C_{1}$ (2) $C_{2} = \frac{C _{1}}{2}$ (3) $C_{1} = 2 C_{2}$ (4) $C_{1} = C_{2}$ 190. $When 0.1 mol M n O_{4}^{2 -} is oxidised the quantity of electricity required to completely oxidise M n O_{4}^{2 -} to M n O_{4}^{-} is$ (1) $96500 C$ (2) $2 \times 96500 C$ (3) $9650 C$ (4) $96.50 C$ 191. $Molar conductivities at infinite dilution \land^{\circ} m for Ba (OH)_{2} BaCl_{2} and NH_{4} Cl are 457.0, 240.6 and 2130 Scm^{2} mol^{- 1} respectively. The \land_{m}^{\circ} for ammonium hydroxide (in Scm^{2} mol^{- 1}) is$ (1) $1683.2$ (2) $1080.2$ (3) $2130.0$ (4) $2238.2$ 192. $Identify the factor from the following that does not affect electrolytic conductance of a solution.$ (1) $The nature of the electrolyte added.$ (2) $The nature of the electrode used.$ (3) $Concentration of the electrolyte.$ (4) $The nature of solvent used.$ 193. $Standard electrode potentials for a few half cells are mentioned below:. E_{Cu^{2 +} / Cu}^{\circ} = 0.34 V, E_{Zn^{2 +} / Zn}^{\circ} = - 0.76 V E_{Ag^{+} / Ag}^{\circ} = 0.80 V, E_{Mg^{2 +} / Mg}^{\circ} = - 2.37 V Which one of the following cells gives the most negative value of Δ G^{\circ} ?$ (1) $Zn (Zn^{2 +} (1 M)) (Ag^{+} (1 M)) Ag$ (2) $Zn (Zn^{2 +} (1 M)) (Mg^{2 +} (1 M)) Mg$ (3) $Ag (Ag^{+} (1 M)) (Mg^{2 +} (1 M)) Mg$ (4) $Cu (Cu^{2 +} (1 M) ‖ Ag^{+} (1 M)) Ag$ 194. $The standard electrode potential of M^{+} /M in aqueous solution does not depend on$ (1) $Hydration of a gaseous metal ion$ (2) $Sublimation of a solid metal$ (3) $Ionisation of a solid metal atom$ (4) $Ionisation of a gaseous metal atom$ 195. $In dry cell, what acts as negative electrode?$ (1) $Zinc$ (2) $Graphite$ (3) $Ammonium chloride$ (4) $Manganese dioxide$ 196. $Aluminium oxide may be electrolysed at 1000ºC to furnish aluminium metal (At.Mass of Al = 27 amu ; 1 Faraday = 96,500 Coulombs). The cathode reaction is A l^{3 +} + 3 e^{-} ® A l^{0} . To prepare 5.12 kg of aluminium metal by this method, one would require:$ (1) $5.49 \times 1 0^{7} C of electricity$ (2) $1.83 \times 1 0^{7} C of electricity$ (3) $5.49 \times 1 0^{4} C of electricity$ (4) $5.49 \times 1 0^{10} C of electricity$ 197. $On electrolysis of dilute sulphuric acid using platinum electrodes, the product obtained at the anode will be$ (1) $hydrogen$ (2) $oxygen$ (3) $hydrogen sulphide$ (4) $sulphur dioxide.$ 198. $If ' A' is the reactant and ' P' is the product, which one of the following is the correct form of Nernst equation?$ (1) $\frac{[ A ]}{[ P ]} = exp (\frac{RT}{n F} (E - E^{\circ}))$ (2) $\frac{[ A ]}{[ P ]} = exp (\frac{n F}{RT} (E - E^{\circ}))$ (3) $\frac{[ A ]}{[ P ]} = exp (- \frac{n F}{RT} (E - E^{\circ}))$ (4) $E = E^{\circ} - \frac{RT}{nF} ln \frac{[ A ]}{[ P ]}$ 199. $For the following cell, Zn(s) \| Z n S O_{4} (aq) \|\| C u S O_{4} (aq) \| Cu(s) when the concentration of Z n^{2 +} is 10 times the concentration of C u^{2 +}, the expression for DG (in J m o l^{-1}) is [F is Faraday constant; R is gas constant; T is temperature; Eº(cell) = 1.1 V]$ (1) $2.303 RT + 1.1 F$ (2) $1.1 F$ (3) $2.303 RT - 2.2 F$ (4) $-2.2 F$ 200. $How is electrical conductance of a conductor related with length and area of cross section of the conductor?$ (1) $G = l \cdot a \cdot κ^{- 1}$ (2) $G = κ \cdot a \cdot l^{- 1}$ (3) $G = κ \cdot l \cdot a^{- 1}$ (4) $G = κ \cdot l \cdot a^{- 2}$ 201. $By passing electric current, NaClO_{3} is converted into NaClO_{4} according to the following equation: NaClO_{3} + H_{2} O ⟶ NaClO_{4} + H_{2} How many moles of NaClO_{4} will be formed when three faradays of charge is passed through NaClO_{3} ?$ (1) $0.75$ (2) $3.0$ (3) $1.5$ (4) $1.0$ 202. $Same amount of electricity is passed through aqueous solutions of AgNO_{3} and CuSO_{4} . The number of Ag and Cu atoms deposited are x and y respectively. The correct relationship between x and y is$ (1) $x < y$ (2) $x = 2 y$ (3) $x = y$ (4) $y = 2 x$ 203. $A lead storage battery is discharged. During the charging of this battery, the reaction that occurs at anode, is$ (1) $PbSO_{4} (s) + 2 e^{-} ⟶ Pb (s) + SO_{4}^{2 -} (aq)$ (2) $PbSO_{4} (s) + 2 H_{2} O (l) ⟶ PbO_{2} (s) + SO_{4}^{2 -} (aq) + 4 H^{+} (aq) + 2 e^{-}$ (3) $PbSO_{4} (s) ⟶ Pb^{2 +} (aq) + SO_{4}^{2 -} (aq)$ (4) $PbSO_{4} (s) + 2 H_{2} O (l) + 2 e^{-} ⟶ PbO_{2} (s) + SO_{4}^{2 -} (aq) + 2 H^{+} (aq)$ 204. $Specific conductance of 0.1 M HNO_{3} is 6.3 \times 10^{- 2} ohm^{- 1} cm^{- 1} . The molar conductance of the solution is$ (1) $6.300 ohm^{- 1} cm^{2} mol^{- 1}$ (2) $63.0 ohm^{- 1} cm^{2} mol^{- 1}$ (3) $630 ohm^{- 1} cm^{2} mol^{- 1}$ (4) $315 ohm^{- 1} cm^{2} mol^{- 1}$ 205. $On charging the lead storage battery, the oxidation state of lead changes from x_{1} to y_{1} at the anode and from x_{2} to y_{2} at the cathode. The values of x_{1}, y_{1}, x_{2}, y_{2} are respectively:$ (1) $0, + 2, + 4, + 2$ (2) $+ 2, 0, 0, + 4$ (3) $+ 4, + 2, 0, + 2$ (4) $+ 2, 0, + 2, + 4$ 206. $For the cell reaction, Cu / Cu^{2 +} (0.1 M) ∥ Cu^{2 +} (1.0 M) / Cu, the emf of the cell at 25^{\circ} C is (E_{Cu^{2 +} / Cu} = 0.34 V) z$ (1) $0.059 V$ (2) $0.311 V$ (3) $0.369 V$ (4) $0.029 V$ 207. $A KC solution of conductivity 0.14 S m^{- 1} shows a resistance of 4.19Ω in a conductivity cell. If the same cellis filled with an HCl solution, the resistance drops to 1.03Ω . The conductivity of the HC 1 solution is____\times 10^{- 2} S m^{- 1} . (Roundoff to the Nearest Integer).$ 208. $The quantity of electricity in Faraday needed to reduce 1 mol of C r_{2} O_{7}^{2 -} to C r^{3 +} is_________.$ 209. $Emf of the following cell at 298 K in Vis x \times 10^{- 2} . Zn (Z n^{2 +} (0.1 M)) \| A g^{+} (0.01 M) \| Ag The value of x is ____ (Rounded off to the nearest integer) [Given: E_{Z n^{2 +} / Zn}^{0} = - 0.76 V, E_{Ag^{+} / Ag}^{0} = + 0.80 V, \frac{2.303 RT}{F} = 0.059]$ 210. $For the disproportionate reaction 2 C u^{+} (aq) ⇌ Cu (s) + C u^{2 +} (aq) at 298 K. ln K where K is the Equibilirium constant) is \times 10^{- 1} Given: (E_{\frac{C u ^{2 +}}{Cu ^{+}}}^{0} = 0.16 V; E_{\frac{C u ^{+}}{Cu}}^{0} = 0.52 V; \frac{RT}{F} = 0.025)$