Question 1

In an electrochemical reaction, the change in Gibbs free energy ($\Delta$G) is related to the potential drop across the electrode-electrolyte interface
A) linearly
B) exponentially
C) logarithmically
D) none of the above

Accepted Answer

The change in Gibbs free energy in an electrochemical reaction is directly proportional to the potential difference across the electrode-electrolyte interface, according to the Nernst equation. Therefore, the relationship between Gibbs free energy and potential drop is linear.

Question 2

As the potential is changed, the rate constant of a chemical reaction
A) changes linearly
B) changes quadratically
C) does not change at all
D) changes exponentially

Accepted Answer

The rate constant of a chemical reaction is related to the activation energy of the reaction. As the potential is changed, the activation energy changes, which can result in an exponential change in the rate constant. Thus, the best choice is D, which states that the rate constant changes exponentially.

Question 3

When the concentration of ions in solution is very low, (< 1 mM) Helmholtz model offers a better description of the double layer capacitor.

Accepted Answer

At very low ion concentrations (< 1 mM), the Gouy-Chapman model, rather than the Helmholtz model, provides a better description of the electrical double layer because it accounts for the diffuse nature of ions in the solution.

Question 4

For a capacitor with a certain capacitance (C), the relationship between current(i) and potential (E) in time (t) domain is given by
A) $$i = \frac { 1 } { C } \frac { dE } { d t }$$
B) $$i = C \frac { d E } { d t }$$
C) $$E = \frac { 1 } { C } \frac { d i } { d t }$$
D) $$E = C \frac { d i } { d t }$$

Accepted Answer

This is the correct formula for the relationship between current and potential in a capacitor in time domain. It states that current is equal to the capacitance multiplied by the rate of change of potential with respect to time.

Question 5

If a metal, such as Cu, is used as a working electrode, and another piece of the same metal is used as a reference electrode, then any potential applied is evenly divided between the working and reference electrode.

Accepted Answer

Any potential applied to the working electrode will cause a redox reaction to occur at the surface of the electrode, which will generate a potential difference between the working electrode and the reference electrode. Therefore, the potential applied will not be evenly divided between the working and reference electrode.

Question 6

Given $$j = \sqrt { - 1 }$$ 
, if a sinusoidal potential of angular frequency ($\omega$) is applied, then the impedance of an inductor with an inductance (L Henry) is given in complex notation as
A) $$\frac { 1 } { j \omega L }$$
B) $$\omega L$$
C) $$j \omega L$$
D) $$\frac { 1 } { \omega L }$$

Accepted Answer

The impedance of an inductor is given by $$Z_L = j\omega L$$ where $$\omega$$ is the angular frequency and L is the inductance. Since $$j=\sqrt{-1}$$, the given impedance in complex notation is $$j\omega L$$. Therefore, the correct choice is C.

Question 7

A three-electrode system is used in lab experiments so that
A) load is divided evenly between all electrodes
B) potential change across working electrode can be controlled
C) potential at the counter electrode is fixed
D) current at the working electrode is fixed

Accepted Answer

In a three-electrode system, the potential change across the working electrode can be controlled by adjusting the potential at the reference electrode. The counter electrode is used to complete the circuit and does not play a role in controlling the potential at the working electrode. The current at the working electrode is not necessarily fixed, but can be controlled by adjusting the potential and/or concentration of the electrolyte. Therefore, B is the best choice.

Question 8

The role of supporting electrolyte is to
A) support the electrochemical cell
B) increase the effective area of the working electrode
C) decrease reference electrode impedance
D) decrease solution resistance

Accepted Answer

The role of the supporting electrolyte is to decrease solution resistance, which allows for better electron transfer between the working and reference electrodes. This improves the efficiency and accuracy of the electrochemical cell.

Question 9

The impedance of an ideal inductor will have a phase of
A) 0 °
B) -90 °
C) +90 °
D) 180 °

Accepted Answer

The impedance of an ideal inductor leads the current by 90 degrees, indicating a phase of +90°.

Question 10

An inductor of inductance (L) and a capacitor of capacitance (c) are connected in series. The net impedance of this circuit is
A) $$j \omega L + \frac { j } { \omega C }$$
B) $$j \omega L - \frac { j } { \omega C }$$
C) $$j \omega C - \frac { 1 } { j \omega L }$$
D) $$j \omega C + \frac { 1 } { j \omega L }$$

Accepted Answer

The net impedance of a series LC circuit is given by the sum of the inductive reactance ($j\omega L$) and the capacitive reactance ($-\frac{j}{\omega C}$). The correct formula is $j\omega L - \frac{j}{\omega C}$.

Question 11

An ideal reference electrode is polarizable.

Accepted Answer

An ideal reference electrode is not polarizable. It maintains a constant potential regardless of the solution it is in, and does not react or contribute to the electrochemical reaction taking place.

Question 12

Given $$j = \sqrt { - 1 }$$ 
, if a sinusoidal potential of angular frequency ($\theta$ ) is applied, then the admittance of a capacitor with capacitance (C Farad) is given in complex notation as
A) $$\Gamma \frac { d \theta } { d t } = k _ { 1 } ( 1 - \theta ) - k _ { - 1 } \theta - k _ { 2 } \theta + k _ { - 2 } C _ { M _ { s a } ^ { 2 } }$$
B) $$\theta _ { ss } = \frac { k _ { 1 \dot { dc } } } { k _ { 1 \dot { dc} } + k _ { 2 } }$$
C) $$\theta _ { s s } = \frac { k _ { 1 dc } } { k _ { 1 \dot { dc } } + k _ { - 1  \dot { dc } } + k _ { 2 } + k _ { - 2 } }$$
D) $\theta_{ss}=\frac{k_{1 d c}+k_{-2} C_{M_{sol}^+2}}{k_{1 d c}+k_{-l d c}+k_{2}+k_{-2} C_{M_{sol}^{+2}}}$

Accepted Answer

The answer of Given \[j = \sqrt { - 1...

Question 13

For an ideal reference electrode, the impedance should be very large.

Accepted Answer

For an ideal reference electrode, the impedance should be very low to ensure accurate and stable potential measurements.

Question 14

In the potentiodynamic polarization data of a simple electron transfer reaction (Fig. below), region (II) is 
A) kinetic limited
B) mixed control region
C) diffusion-limited
D) adsorption limited.

Accepted Answer

The answer of In the potentiodynamic polarization data of a...

Question 15

Consider an electrical circuit shown below. For a given value of R₁, R₂_, and C₂, the impedance at a wide range of frequencies can be calculated and plotted as a complex plane plot and Bode plots. If the capacitance C₂ is changed, A) Shape of the complex plane plot will remain the same, but the points will move in the same curve B) location of the peak in phase vs. frequency will change C) both of the above D) none of the above

Accepted Answer

The answer of Consider an electrical circuit shown below.
 For...

Question 16

In chrono amperometry, ____________ is measured as a function of _____________

Accepted Answer

The answer of In chrono amperometry, ____________ is measured as...

Question 17

Consider three resistors, R₁ = 150 $\Omega$, R₂ = 200 $\Omega$ and R₃ = 250 $\Omega$. When they are connected in series, the net impedance is (i)__________ $\Omega$ and when they are connected in parallel, the net impedance is (ii)___________ $\Omega$

Accepted Answer

The answer of Consider three resistors, R₁ = 150 ...

Question 18

A resistor with resistance (R) is connected in parallel with an inductor with an inductance (L). The net impedance of the circuit is given by
A) 
 $$R + j \omega L$$ ,
B) $$R - j \omega L$$
C) $$\frac { 1 } { \frac { 1 } { R } + \frac { 1 } { j \omega L } }$$
D) $$\frac { 1 } { \frac { 1 } { R } - \frac { 1 } { j \omega L } }$$

Accepted Answer

When a resistor and an inductor are connected in parallel, the total impedance of the circuit is given by
$$Z_{total} = \frac{1}{\frac{1}{R}+\frac{1}{j\omega L}}$$
Simplifying the above equation, we get
$$Z_{total} = \frac{j\omega L R}{j\omega L +R}$$
Therefore, the net impedance of the circuit is C) $$\frac { 1 } { \frac { 1 } { R } + \frac { 1 } { j \omega L } }$$

Question 19

The impedance of an ideal capacitor will have a phase of
A) 0 °
B) -90 °
C) +90 °
D) 180 °

Accepted Answer

The impedance of an ideal capacitor is given by Z = -jXC, where Xc is the capacitive reactance. Since Xc = 1/ωC, where ω is the angular frequency and C is the capacitance, the impedance of an ideal capacitor is inversely proportional to frequency. As frequency increases, the capacitive reactance decreases, and the impedance becomes dominated by the resistance of the wires and other components in the circuit. At low frequencies, however, the capacitive reactance can be much larger than the resistance, leading to a phase shift of -90° between the voltage and current across the capacitor. Therefore, the answer is B) -90°.

Question 20

Using the circuit given below, calculate the impedance at a frequency of 10^-5 Hz. Here, R_sol = 10 $\Omega$, R_t = 100 $\Omega$, C_dl = 10 $\mu$ F. Round the impedance values to one decimal. Z_Re = (i) __________ $\Omega$and Z_Im = (ii) ___________ $\Omega$.

Accepted Answer

The answer of Using the circuit given below, calculate the...

Quiz 1: Introduction

In an electrochemical reaction, the change in Gibbs free energy ( $\Delta$ G) is related to the potential drop across the electrode-electrolyte interface

As the potential is changed, the rate constant of a chemical reaction

When the concentration of ions in solution is very low, (< 1 mM) Helmholtz model offers a better description of the double layer capacitor.

For a capacitor with a certain capacitance (C) , the relationship between current(i) and potential (E) in time (t) domain is given by

If a metal, such as Cu, is used as a working electrode, and another piece of the same metal is used as a reference electrode, then any potential applied is evenly divided between the working and reference electrode.

Given $j = \sqrt { - 1 }$ , if a sinusoidal potential of angular frequency ( $\omega$ ) is applied, then the impedance of an inductor with an inductance (L Henry) is given in complex notation as

A three-electrode system is used in lab experiments so that

The role of supporting electrolyte is to

The impedance of an ideal inductor will have a phase of

An inductor of inductance (L) and a capacitor of capacitance (c) are connected in series. The net impedance of this circuit is

An ideal reference electrode is polarizable.

Given $j = \sqrt { - 1 }$ , if a sinusoidal potential of angular frequency ( $\theta$ ) is applied, then the admittance of a capacitor with capacitance (C Farad) is given in complex notation as

For an ideal reference electrode, the impedance should be very large.

In the potentiodynamic polarization data of a simple electron transfer reaction (Fig. below) , region (II) is

Consider an electrical circuit shown below. For a given value of R₁, R₂_, and C₂, the impedance at a wide range of frequencies can be calculated and plotted as a complex plane plot and Bode plots. If the capacitance C₂ is changed,

In chrono amperometry, is measured as a function of _

Consider three resistors, R₁ = 150 $\Omega$ , R₂ = 200 $\Omega$ and R₃ = 250 $\Omega$ . When they are connected in series, the net impedance is (i) $\Omega$ and when they are connected in parallel, the net impedance is (ii)_ $\Omega$

A resistor with resistance (R) is connected in parallel with an inductor with an inductance (L) . The net impedance of the circuit is given by

The impedance of an ideal capacitor will have a phase of

Quiz 1: Introduction

In an electrochemical reaction, the change in Gibbs free energy ( Δ\DeltaΔ G) is related to the potential drop across the electrode-electrolyte interface

As the potential is changed, the rate constant of a chemical reaction

When the concentration of ions in solution is very low, (< 1 mM) Helmholtz model offers a better description of the double layer capacitor.

For a capacitor with a certain capacitance (C) , the relationship between current(i) and potential (E) in time (t) domain is given by

If a metal, such as Cu, is used as a working electrode, and another piece of the same metal is used as a reference electrode, then any potential applied is evenly divided between the working and reference electrode.

Given j=−1j = \sqrt { - 1 }j=−1​ , if a sinusoidal potential of angular frequency ( ω\omegaω ) is applied, then the impedance of an inductor with an inductance (L Henry) is given in complex notation as

A three-electrode system is used in lab experiments so that

The role of supporting electrolyte is to

The impedance of an ideal inductor will have a phase of

An inductor of inductance (L) and a capacitor of capacitance (c) are connected in series. The net impedance of this circuit is

An ideal reference electrode is polarizable.

Given j=−1j = \sqrt { - 1 }j=−1​ , if a sinusoidal potential of angular frequency ( θ\thetaθ ) is applied, then the admittance of a capacitor with capacitance (C Farad) is given in complex notation as

For an ideal reference electrode, the impedance should be very large.

In the potentiodynamic polarization data of a simple electron transfer reaction (Fig. below) , region (II) is

Consider an electrical circuit shown below. For a given value of R1, R2, and C2, the impedance at a wide range of frequencies can be calculated and plotted as a complex plane plot and Bode plots. If the capacitance C2 is changed,

In chrono amperometry, ____________ is measured as a function of _____________

Consider three resistors, R1 = 150 Ω\OmegaΩ , R2 = 200 Ω\OmegaΩ and R3 = 250 Ω\OmegaΩ . When they are connected in series, the net impedance is (i)__________ Ω\OmegaΩ and when they are connected in parallel, the net impedance is (ii)___________ Ω\OmegaΩ

A resistor with resistance (R) is connected in parallel with an inductor with an inductance (L) . The net impedance of the circuit is given by

The impedance of an ideal capacitor will have a phase of

Using the circuit given below, calculate the impedance at a frequency of 10-5 Hz. Here, Rsol = 10 Ω\OmegaΩ , Rt = 100 Ω\OmegaΩ , Cdl = 10 μ\muμ F. Round the impedance values to one decimal. ZRe = (i) __________ Ω\OmegaΩ and ZIm = (ii) ___________ Ω\OmegaΩ .

In an electrochemical reaction, the change in Gibbs free energy ( $\Delta$ G) is related to the potential drop across the electrode-electrolyte interface

Given $j = \sqrt { - 1 }$ , if a sinusoidal potential of angular frequency ( $\omega$ ) is applied, then the impedance of an inductor with an inductance (L Henry) is given in complex notation as

Given $j = \sqrt { - 1 }$ , if a sinusoidal potential of angular frequency ( $\theta$ ) is applied, then the admittance of a capacitor with capacitance (C Farad) is given in complex notation as

Consider an electrical circuit shown below. For a given value of R₁, R₂_, and C₂, the impedance at a wide range of frequencies can be calculated and plotted as a complex plane plot and Bode plots. If the capacitance C₂ is changed,

In chrono amperometry, is measured as a function of _

Consider three resistors, R₁ = 150 $\Omega$ , R₂ = 200 $\Omega$ and R₃ = 250 $\Omega$ . When they are connected in series, the net impedance is (i) $\Omega$ and when they are connected in parallel, the net impedance is (ii)_ $\Omega$