Electrochemical Cells

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JEE Advanced 2025

LEVELJEE Advanced

An electrochemical cell is fueled by the combustion of butane at 1 bar and 298 K. Its cell potential is $\frac{X}{F} \times 1 0^{3}$ volts, where $F$ is the Faraday constant. The value of $X$ is ______. Use : Standard Gibbs energies of formation at 298 K are : $Δ_{f} G_{CO_{2}}^{\circ} = - 394 kJ mol^{- 1}$ ; $Δ_{f} G_{water}^{\circ} = - 237 kJ mol^{- 1}$ ; $Δ_{f} G_{butane}^{\circ} = - 18 kJ mol^{- 1}$

JEE Advanced 2014

LEVELJEE Main

In a galvanic cell , the salt bridge -

* Multiple Correct Options

(A)

Does not participate chemically in the cell reaction

(B)

Stops the diffusion of ions from one electrode to another

(C)

Is necessary for the occurence of the cell reaction

(D)

Ensures mixing of the two electrolytic solutions

JEE Advanced 2018

LEVELJEE Advanced

Consider an electrochemical cell: $A (s) ∣ A^{n +} (a q, 2 M) ∣∣ B^{2 n +} (a q, 1 M) ∣ B (s)$ . The value of $Δ H^{θ}$ for the cell reaction is twice that of $Δ G^{θ}$ at $300 K$ . If the emf of the cell is zero, the $Δ S^{θ}$ (in $J K^{- 1} mol^{- 1}$ ) of the cell reaction per mole of $B$ formed at $300 K$ is______. (Given : $ln (2) = 0.7$ , $R$ (universal gas constant) $= 8.3 J K^{- 1} mol^{- 1}$ . $H$ , $S$ and $G$ are enthalpy, entropy and Gibbs energy, respectively.)

JEE Advanced 2022

LEVELJEE Advanced

The correct option(s) about entropy ( $S$ ) is(are) [ $R = gas constant$ , $F = Faraday constant$ , $T = Temperature$ ]

* Multiple Correct Options

(A)

For the reaction,

M (s) + 2 H^{+} (a q) \to H_{2} (g) + M^{2 +} (a q)

, if

\frac{d E _{cell}}{d T} = \frac{R}{F}

, then the entropy change of the reaction is

R

(assume that entropy and internal energy changes are temperature independent).

(B)

The cell reaction,

Pt (s) ∣ H_{2} (g, 1 bar) ∣ H^{+} (a q, 0.01 M) ∥ H^{+} (a q, 0.1 M) ∣ H_{2} (g, 1 bar) ∣ Pt (s)

, is an entropy driven process.

(C)

For racemization of an optically active compound,

Δ S > 0

(D)

Δ S > 0

, for

[Ni (H_{2} O)_{6}]^{2 +} + 3 en \to [Ni (en)_{3}]^{2 +} + 6 H_{2} O

(where

en = ethylenediamine

JEE Advanced 2018

LEVELJEE Main

For the electrochemical cell, $Mg(s) ∣ Mg^{2 +} (aq, 1 M) ∣∣ Cu^{2 +} (aq, 1 M) ∣ Cu(s)$ the standard emf of the cell is $2.70 V$ at $300 K$ . When the concentration of $Mg^{2 +}$ is changed to $x M$ , the cell potential changes to $2.67 V$ at $300 K$ . The value of $x$ is______. (given, $\frac{F}{R} = 11500 K V^{- 1}$ , where $F$ is the Faraday constant and $R$ is the gas constant, $ln (10) = 2.30$ )

JEE Advanced 2020

LEVELJEE Advanced

Consider a 70% efficient hydrogen-oxygen fuel cell working under standard conditions at 1 bar and 298 K. Its cell reaction is $H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l)$ . The work derived from the cell on the consumption of $1.0 \times 1 0^{- 3} mol$ of $H_{2} (g)$ is used to compress 1.00 mol of a monoatomic ideal gas in a thermally insulted container. What is the change in the temperature (in K) of the ideal gas ? The standard reduction potentials for the two half-cells are given below. $O_{2} (g) + 4 H^{+} (a q .) + 4 e^{-} \to 2 H_{2} O (l), E^{\circ} = 1.23 V$ , $2 H^{+} (a q .) + 2 e^{-} \to H_{2} (g), E^{\circ} = 0.00 V$ . Use $F = 96500 C mol^{- 1}, R = 8.314 J mol^{- 1} K^{- 1}$

JEE Advanced 2017

LEVELJEE Main

For the following cell : $Zn(s) ∣ ZnSO_{4} (aq.) ∥ CuSO_{4} (aq.) ∣ Cu(s)$ when the concentration of $Zn^{2 +}$ is $10$ times the concentration of $Cu^{2 +}$ , the expression for $Δ G$ (in $J mol^{- 1}$ ) is [ $F$ is Faraday constant, $R$ is gas constant, $T$ is temperature, $E^{\circ} (cell) = 1.1 V$ ]

(A)

2.303 RT + 1.1 F

(B)

2.303 RT - 2.2 F

(C)

1.1 F

(D)

- 2.2 F

JEE Advanced 2015

LEVELJEE Main

All the energy released from the reaction $X \to Y$ , $Δ_{r} G^{\circ} = - 193 kJ mol^{- 1}$ is used for the oxidizing $M^{+}$ and $M^{+} \to M^{3 +} + 2 e^{-}$ , $E^{\circ} = - 0.25 V$ . Under standard conditions, the number of moles of $M^{+}$ oxidized when one mole of X is converted to Y is $[F = 96500 C mol^{- 1}]$

JEE Advanced 2021

LEVELJEE Advanced

Some standard electrode potentials at 298 K are given below: $Pb^{2 +} / Pb - 0.13 V$ $Ni^{2 +} / Ni - 0.24 V$ $Cd^{2 +} / Cd - 0.40 V$ $Fe^{2 +} / Fe - 0.44 V$ To a solution containing $0.001 M$ of $X^{2 +}$ and $0.1 M$ of $Y^{2 +}$ , the metal rods X and Y are inserted (at 298 K) and connected by a conducting wire. This resulted in dissolution of X. The correct combination(s) of X and Y, respectively, is (are) (Given: Gas constant, $R = 8.314 J K^{- 1} mol^{- 1}$ , Faraday constant, $F = 96500 C mol^{- 1}$ )

* Multiple Correct Options

The reduction potential ( $E^{0}$ , in V) of $MnO_{4}^{-} (aq) / Mn (s)$ is _______. [Given : $E_{(MnO_{4}^{-} (aq) / MnO_{2} (s))}^{0} = 1.68 V$ ; $E_{(MnO_{2} (s) / Mn^{2 +} (aq))}^{0} = 1.21 V$ ; $E_{(Mn^{2 +} (aq) / Mn (s))}^{0} = - 1.03 V$ ]

LEVELJEE Main

Given, $E_{F e^{3 +} / F e}^{\circ} = - 0.036 V$ , $E_{F e^{2 +} / F e}^{\circ} = - 0.439 V$ . The value of standard electrode potential for the charge, $F e^{3 +} (a q) + e^{-} ⟶ F e^{2 +} (a q)$ will be

Given below are the half-cell reactions $M n^{2 +} + 2 e^{-} ⟶ M n, E^{\circ} = - 1.18 V$ $2 (M n^{3 +} + e^{-} ⟶ M n^{2 +}), E^{\circ} = + 1.51 V$ The $E^{\circ}$ for $3 M n^{2 +} ⟶ M n + 2 M n^{3 +}$ will be

(A)

- 2.69 V

, the reaction will not occur

(B)

- 2.69 V

the reaction will occur

(C)

- 0.33 V

, the reaction will not occur

(D)

- 0.33 V

, the reaction will occur

JEE Main 2004

LEVELJEE Main

In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

(A)

generate heat

(B)

create potential difference between the two electrodes

(C)

produce high purity water

(D)

remove adsorbed oxygen from electrode surfaces

JEE Main 2017

LEVELJEE Main

Given, $E_{C l_{2} / C l^{-}}^{\circ} = 1.36 V$ , $E_{C r^{3 +} / C r}^{\circ} = - 0.74 V$ , $E_{C r_{2} O_{7}^{2 -} / C r^{3 +}}^{\circ} = 1.33 V$ , $E_{M n O_{4}^{-} / M n^{2 +}}^{\circ} = 1.51 V$ . Among the following, the strongest reducing agent is

(A)

(B)

M n^{2 +}

(C)

C r^{3 +}

(D)

C l^{-}

LEVELJEE Main

Standard reduction 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 are

(A)

B > C > A

(B)

A > B > C

(C)

C > B > A

(D)

A > C > B

JEE Main 2021

LEVELJEE Main

Compound A used as a strong oxidising agent is amphoteric in nature. It is the part of lead storage batteries. Compound A is

(A)

PbO_{2}

(B)

PbO

(C)

PbSO_{4}

(D)

Pb_{3} O_{4}

JEE Main 2021

LEVELJEE Advanced

Consider the cell at $2 5^{\circ} C$ $Z n ∣ Z n^{2 +} (a q), (1 M) ∣∣ F e^{3 +} (a q), F e^{2 +} (a q) ∣ P t (s)$ The fraction of total iron present as $F e^{3 +}$ ion at the cell potential of $1.500 V$ is $x \times 1 0^{- 2}$ . The value of $x$ is ……… . (Nearest integer) (Given, $E_{F e^{3 +} / F e^{2 +}}^{\circ} = 0.77 V$ , $E_{Z n^{2 +} / Z n}^{\circ} = - 0.76 V$ )

JEE Main 2021

LEVELJEE Main

These are physical properties of an element. A. Sublimation enthalpy B. Ionisation enthalpy C. Hydration enthalpy D. Electron gain enthalpy The total number of above properties that affect the reduction potential is ……… (Integer answer)

JEE Main 2020

LEVELJEE Main

Given the electrochemical cell: $E_{Cu^{2 +} ∣ Cu}^{\circ} = + 0.34 V$ $E_{Zn^{2 +} ∣ Zn}^{\circ} = - 0.76 V$ Identify the incorrect statement from the options below for the above cell.

(A)

E_{ext} > 1.1 V

, Zn dissolves at Zn electrode and Cu deposits at Cu electrode.

(B)

E_{ext} = 1.1 V

, no flow of electrons or current occurs.

(C)

E_{ext} > 1.1 V

, electrons flows from Cu to Zn.

(D)

E_{ext} < 1.1 V

, Zn dissolves at anode and Cu deposits at cathode.

JEE Main 2016

LEVELBoard

Galvanisation is applying a coating of

Emf of the following cell at $298 K$ in $V$ is $x \times 1 0^{- 2}$ , $Zn ∣ Zn^{2 +} (0.1 M) ∣∣ Ag^{+} (0.01 M) ∣ Ag$ The value of $x$ is ......... . (Rounded off to the nearest integer). [Given, $E_{Zn^{2 +} / Zn}^{\circ} = - 0.76 V$ , $E_{Ag^{+} / Ag}^{\circ} = + 0.80 V$ , $\frac{2.303 R T}{F} = 0.059$ ]

JEE Main 2020

LEVELJEE Main

Given that the standard potentials ( $E^{\circ}$ ) of $C u^{2 +} / C u$ and $C u^{+} / C u$ are $0.34 V$ and $0.522 V$ respectively, the $E^{\circ}$ of $C u^{2 +} / C u^{+}$ is

(A)

- 0.158 V

(B)

+ 0.158 V

(C)

- 0.182 V

(D)

0.182 V

JEE Main 2020

LEVELJEE Main

For the disproportionation reaction $2 Cu^{+} (a q) ⇌ Cu (s) + Cu^{2 +} (a q)$ at 298 K, $ln K$ (where $K$ is the equilibrium constant) is ......... $\times 1 0^{- 1}$ . Given : ( $E_{Cu^{2 +} / Cu^{+}}^{\circ} = 0.16 V$ , $E_{Cu^{+} / Cu}^{\circ} = 0.52 V$ and $\frac{R T}{F} = 0.025$ )

JEE Main 2019

LEVELJEE Main

Given the equilibrium constant ( $K_{c}$ ) of the reaction : $C u (s) + 2 A g^{+} (a q) \to C u^{2 +} (a q) + 2 A g (s)$ is $10 \times 1 0^{15}$ , calculate the $E_{ce l l}^{\circ}$ of this reaction at 298 K. $[2.303 \frac{R T}{F} at 298 K = 0.059 V]$

For the redox reaction $Z n (s) + C u^{2 +} (0.1 M) ⟶ Z n^{2 +} (1 M) + C u (s)$ taking place in a cell, $E_{ce l l}^{\circ}$ is $1.10 V$ . $E_{ce l l}$ for the cell will be $(2.303 \frac{R T}{F} = 0.0591)$

In a galvanic cell , the salt bridge -

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The correct option(s) about entropy (S) is(are) [R=gas constant, F=Faraday constant, T=Temperature]

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Given, EFe3+/Fe∘​=−0.036 V, EFe2+/Fe∘​=−0.439 V. The value of standard electrode potential for the charge, Fe3+(aq)+e−⟶Fe2+(aq) will be

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Given below are the half-cell reactions Mn2++2e−⟶Mn,E∘=−1.18 V 2(Mn3++e−⟶Mn2+),E∘=+1.51 V The E∘ for 3Mn2+⟶Mn+2Mn3+ will be

In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Standard reduction 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 are

Compound A used as a strong oxidising agent is amphoteric in nature. It is the part of lead storage batteries. Compound A is

These are physical properties of an element. A. Sublimation enthalpy B. Ionisation enthalpy C. Hydration enthalpy D. Electron gain enthalpy The total number of above properties that affect the reduction potential is ……… (Integer answer)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Given the electrochemical cell: ECu2+∣Cu∘​=+0.34 V EZn2+∣Zn∘​=−0.76 V Identify the incorrect statement from the options below for the above cell.

Galvanisation is applying a coating of

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Given that the standard potentials (E∘) of Cu2+/Cu and Cu+/Cu are 0.34 V and 0.522 V respectively, the E∘ of Cu2+/Cu+ is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } For the redox reaction Zn(s)+Cu2+(0.1 M)⟶Zn2+(1 M)+Cu(s) taking place in a cell, Ecell∘​ is 1.10 V. Ecell​ for the cell will be (2.303FRT​=0.0591)

The correct option(s) about entropy ( $S$ ) is(are) [ $R = gas constant$ , $F = Faraday constant$ , $T = Temperature$ ]

Given, $E_{F e^{3 +} / F e}^{\circ} = - 0.036 V$ , $E_{F e^{2 +} / F e}^{\circ} = - 0.439 V$ . The value of standard electrode potential for the charge, $F e^{3 +} (a q) + e^{-} ⟶ F e^{2 +} (a q)$ will be

Given below are the half-cell reactions $M n^{2 +} + 2 e^{-} ⟶ M n, E^{\circ} = - 1.18 V$ $2 (M n^{3 +} + e^{-} ⟶ M n^{2 +}), E^{\circ} = + 1.51 V$ The $E^{\circ}$ for $3 M n^{2 +} ⟶ M n + 2 M n^{3 +}$ will be

Standard reduction 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 are

Given the electrochemical cell: $E_{Cu^{2 +} ∣ Cu}^{\circ} = + 0.34 V$ $E_{Zn^{2 +} ∣ Zn}^{\circ} = - 0.76 V$ Identify the incorrect statement from the options below for the above cell.

Given that the standard potentials ( $E^{\circ}$ ) of $C u^{2 +} / C u$ and $C u^{+} / C u$ are $0.34 V$ and $0.522 V$ respectively, the $E^{\circ}$ of $C u^{2 +} / C u^{+}$ is

For the redox reaction $Z n (s) + C u^{2 +} (0.1 M) ⟶ Z n^{2 +} (1 M) + C u (s)$ taking place in a cell, $E_{ce l l}^{\circ}$ is $1.10 V$ . $E_{ce l l}$ for the cell will be $(2.303 \frac{R T}{F} = 0.0591)$