Question 1

Which of the following best describes the electric double layer at a solid-liquid interface?

Accepted Answer

A region where ions from the solution build up next to the charged surface, creating a potential difference.

Question 2

What is the relationship between electrostatic potential and electron energy at an interface?

Accepted Answer

Electrostatic potential and electron energy run in opposite directions.

Question 3

Which equation correctly expresses the capacitance $$C of a $$parallel plate capacitor with dielectric?

Accepted Answer

$$C = \frac{\varepsilon_r \$$varepsilon_0$$ a}{\ell}$$

Question 4

Which material would have the highest interfacial capacitance for a 1 μm thick layer, based on its dielectric constant?

Accepted Answer

Lead zirconium titanate

Question 5

What is the Debye length $$\lambda_D in an $$electrolyte solution, and what does it represent?

Accepted Answer

The distance over which the electric potential decreases by a factor of $$1/e$$ due to ionic screening.

Question 6

Which formula gives the Debye length $$\lambda_D$$ for an electrolyte solution?

Accepted Answer

$$\lambda_D = \sqrt{\frac{\varepsilon_r \$$varepsilon_0$$ RT}{2F^2$ I_{mo} \rho}}$$

Question 7

At the solid-liquid interface, what happens to the solvation sphere of an ion after electron transfer?

Accepted Answer

It readjusts to accommodate the new charge state.

Question 8

Which process is most closely associated with the inner Helmholtz layer at a solid-liquid interface?

Accepted Answer

Adsorption of specifically bound ions.

Question 9

What is the point of zero charge (PZC) at an electrode interface?

Accepted Answer

The potential at which the electrode has no net charge.

Question 10

Which equation describes the electrochemical potential $$\bar{\mu}_{Oz^+} of an $$ion at the interface?

Accepted Answer

$$\bar{\mu}_{Oz^+} = \mu_{Oz^+} + zF\phi_s$$

Question 11

In an electrochemical cell, what determines whether reduction or oxidation occurs at the solid-liquid interface?

Accepted Answer

The sign and magnitude of $$\phi_M - \phi_S.$$

Question 12

Which of the following is a real-world application of interfacial capacitance?

Accepted Answer

Field-effect transistors (FETs)

Question 13

What is the main difference between physisorption and chemisorption at an interface?

Accepted Answer

Physisorption involves weak van der Waals forces, while chemisorption involves strong chemical bonding.

Question 14

Which equation describes the electrosorption isotherm for an ion at an interface?

Accepted Answer

$$K_a X = \frac{	heta}{1-	heta} \exp\left(\frac{\phi_M - \phi_s F}{RT}ight)$$

Question 15

Which of the following best explains why capacitance increases dramatically in an electrolyte compared to a vacuum?

Accepted Answer

The presence of mobile ions allows for much greater charge separation at the interface.

Question 16

Which layer is closest to the solid surface in the double layer model?

Accepted Answer

Inner Helmholtz layer

Question 17

What is the thermodynamic driving force for electron transfer at a solid-liquid interface?

Accepted Answer

The difference in electrochemical potential between the metal and the solution.

Question 18

Which equation gives the cell potential $$E_{cell}$$ for a reaction $$Oz^+ + qe^- \rightarrow R(z-q)^+$$?

Accepted Answer

$$E_{cell} = -\frac{1}{qF}(\bar{\mu}_{R(z-q)^+} - \bar{\mu}_{Oz^+} - q\bar{\mu}_{e^-})$$

Question 19

Which of the following is NOT a factor that increases interfacial capacitance?

Accepted Answer

Increasing the voltage difference $$\Delta \phi$$ across the interface

Solid, Liquids, and Interfaces: Electric Fields and Electron Transfer at Interfaces

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