Electrochemistry - Physical Chemistry - Chemistry Previous Year Questions

1

2011 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2011

For a 1 molal aqueous NaCl solution, the mean ionic activity coefficient (γ±) and the Debye-Hückel Limiting Law constant (A) are related as

A

\(\log \gamma_\pm = \sqrt{2} A\)

B

\(\log \gamma_\pm = -\sqrt{2} A\)

C

\(\gamma_\pm = 10^A\)

D

\(\gamma_\pm = 10^{-A}\)

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2

2011 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2011

For the concentration cell
\[\text{M} \mid \text{M}^+ (\text{aq} 0.01\ \text{mol dm}^{-3}) \mid \mid \text{M}^+ (\text{aq} 0.1\ \text{mol dm}^{-3}) \mid \text{M}\]
the EMF (E) of the cell at a temperature (T) equals

A

\(2.303 \frac{RT}{F}\)

B

\(-2.303 \frac{RT}{F}\)

C

\(E^0_{M^+/M} + 2.303 \frac{RT}{F}\)

D

\(E^0_{M^+/M} - 2.303 \frac{RT}{F}\)

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3

2012 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2012

At 298 K, the EMF of the cell
Pt | H₂(1 bar) | H⁺(solution)||Cl^– | Hg₂Cl₂ | Hg
is 0.7530 V. The standard potential of the calomel electrode is 0.2802 V. If the liquid junction potential is zero, the pH of the solution is

A

4.7

B

7.4

C

8.0

D

12.7

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4

2012 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2012

For the following reaction
2MnO₄⁻ + 5H₂C₂O₄ + 6H⁺ → 2Mn²⁺ + 8H₂O + 10CO₂
E°(MnO₄⁻/Mn²⁺) = +1.51 V and E°(CO₂/H₂C₂O₄) = −0.49 V.
At 298 K, the equilibrium constant is

A

10⁵⁸⁰

B

10³³⁸

C

10³⁰⁸

D

10⁵³³

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5

2013 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2013

For the determination of solubility product (K_sp) of Fe(OH)₃, the appropriate cell representation and its emf, respectively, are

A

{Fe|Fe(OH)₃(s)|OH^-(aq)Fe³⁺(aq)|Fe}, -0.750 V

B

{Fe|Fe³⁺(aq)OH^-(aq)|Fe(OH)₃(s)|Fe}, -0.750 V

C

{Fe|Fe(OH)₃(s)|OH^-(aq)Fe³⁺(aq)|Fe}, +0.750 V

D

{Fe|Fe³⁺(aq)OH^-(aq)|Fe(OH)₃(s)|Fe}, -0.822 V

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6

2014 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2014

A platinum electrode is immersed in a solution containing 0.1 M Fe²⁺ and 0.1 M Fe³⁺. Its potential is found to be 0.77 V against SHE. Under standard conditions and considering activity coefficients to be equal to unity, the potential of the electrode, when the concentration of Fe³⁺ is increased to 1 M, is ______________

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7

2019 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2019

Consider the electrochemical cell
M(s)|MI₂(s)|MI₂(aq)|M(s)
where 'M' is a metal. At 298 K, the standard reduction potentials are
E⁰_{M²⁺(aq)/M(s)} = −0.12 V, E⁰_MI2(s)/M(s) = −0.36 V and the temperature coefficient is (∂E⁰_cell/∂T)_P = 1.5 × 10⁻⁴ V K⁻¹. At this temperature the standard enthalpy change for the overall cell reaction, Δ_rH⁰, is ______ kJ mol⁻¹. (Round off to two decimal places)
(Faraday constant F = 96500 C mol⁻¹)

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8

2023 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2023

For the galvanic cell: H₂ (g) | HCl (aq) | Cl₂ (g)
the standard electromotive force ($E^0$) value is given by
$E^0 = 1.73 - (1.25 \times 10^{-3})T + (1.00 \times 10^{-6})T^2$
where $E^0$ is in Volts and $T$ is in Kelvin.
For the cell reaction, the standard enthalpy change ($\Delta_r H^0$) at 300 K is ______ kJ mol⁻¹ (rounded off to the nearest integer)
(Given: Faraday constant, $F = 96500$ C mol⁻¹)

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9

2025 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2025

For the cell reaction,
Hg₂Cl₂ (s) + H₂ (1 atm) → 2Hg (l) + 2H⁺ (a = 1) + 2Cl^- (a = 1)
The standard cell potential is ℰ⁰ = 0.2676 V, and (∂ℰ⁰/∂T)_P = -3.19 × 10^-4 V K^-1.
The standard enthalpy change of the reaction (Δ_rH⁰) at 298 K is -x kJ mol^-1.
The value of x is ______ (rounded off to two decimal places).
[Given: Faraday constant F = 96500 C mol^-1]

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10

2007 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2007

For a redox reaction, Cd²⁺ + 2e^- ⇌ Cd, the (E_p)_anodic observed in cyclic voltammetry at hanging mercury drop electrode is −650 mV vs. SCE. The expected value for (E_p)_cathodic is

A

−708 mV

B

−679 mV

C

−650 mV

D

−621 mV

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11

2007 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2007

Given that E_o(Fe³⁺, Fe) = -0.04 V and E_o(Fe²⁺, Fe) = -0.44 V, the value of E_o(Fe³⁺, Fe²⁺) is

A

0.76 V

B

-0.40 V

C

-0.76 V

D

0.40 V

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12

2007 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2007

The activity (M) of \(Mn^{2+}\) ions in the above solution is

A

\(1.0 \times 10^{-4}\)

B

\(2.0 \times 10^{-4}\)

C

\(3.0 \times 10^{-4}\)

D

\(4.0 \times 10^{-4}\)

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13

2010 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2010

The standard reduction potentials at 298 K for single electrodes are given below:

Electrode	Electrode Potential (volt)
Mg²⁺ / Mg	-2.34
Zn²⁺ / Zn	-0.76
Fe²⁺ / Fe	-0.44

From this we can infer that

A

Zn can reduce both Mg²⁺ and Fe²⁺

B

Fe can reduce both Mg²⁺ and Zn²⁺

C

Mg can reduce both Zn²⁺ and Fe²⁺

D

Mg can reduce Zn²⁺ but not Fe²⁺

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14

2015 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2015

The mean ionic activity coefficient of 0.001 molal \(ZnSO_4\) (aq) at 298 K according to the Debye-Hückel limiting law is (Debye-Hückel constant is 0.509 \(mol^{-1/2}\)) ____________________

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15

2015 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2015

The solubility product of \( AgBr(s) \) is \( 5 \times 10^{-13} \) at 298 K. If the standard reduction potential of the half-cell, \( E^0_{Ag|AgBr(s)|Br^-} \) is 0.07 V, the standard reduction potential, \( E^0_{Ag^+|Ag} \) (in volts) is ____________.

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16

2015 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2015

The limiting current (in \(\mu\)A) from the reduction of \(3 \times 10^{-4}\) M \(\mathrm{Pb}^{2+}\), using a dropping mercury electrode (DME) with characteristics, \(m = 3.0\) mg \(\mathrm{s}^{-1}\) and \(t = 3\)s, is (diffusion coefficient of \(\mathrm{Pb}^{2+} = 1.2 \times 10^{-5}\) cm\(^2\) \(\mathrm{s}^{-1}\)) ____________

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17

2017 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2017

The mobility of a univalent ion in aqueous solution is 6.00×10^-8 m² s^-1 V^-1 at 300 K. Its diffusion coefficient at 300 K is X×10^-9 m² s^-1. The value of X is ________________________ (up to two decimal places)

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18

2017 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2017

The standard Gibbs free energy change of the reaction shown below is −2.7 kJ mol^-1.
Sn(s) + Pb²⁺ = Sn²⁺ + Pb(s)
Given that E°(Pb²⁺/Pb) is −0.126 V, the value of E°(Sn²⁺/Sn) in V is ________________________ (up to two decimal places)

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19

2017 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2017

The ionic activity coefficients of Ca²⁺ and F⁻ are 0.72 and 0.28, respectively. The mean activity coefficient of CaF₂ is ________________________ (up to two decimal places)

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20

2017 · Chemistry · Physical Chemistry · Electrochemistry

Chemistry (CY) 2017

The diffusion limiting current (I_d) at a dropping mercury electrode for an aqueous Mg(II) solution of concentration “c” (mol L^-1) is 300 μA. If “c” is increased by 0.1 mol L^-1, I_d increases to 900 μA. The value of “c” (in mol L^-1) is __________ (up to two decimal places)

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