Electrochemistry

The direction of current flow in a galvanic cell is:

Which of the following is NOT used as an electrolyte in the salt bridge?

In an electrochemical cell, if the external potential applied is greater than the $E_{cell}$, the cell behaves as:

The standard electrode potential of a Standard Hydrogen Electrode (SHE) is taken as:

A cell is constructed using $Fe/Fe^{2+}$ and $Sn/Sn^{2+}$ couples. If $E^o_{Fe^{2+}/Fe} = -0.44 V$ and $E^o_{Sn^{2+}/Sn} = -0.14 V$, the $E^o_{cell}$ will be:

What is the cell potential of a concentration cell consisting of two silver electrodes in $0.01 M$ and $0.1 M$ $AgNO_3$ solutions at $298 K$?

Which of the following conditions is required for $E_{cell}$ to be equal to $E^o_{cell}$?

A corrosion scientist is studying the rust formation on an iron pipe. The process acts like a miniature electrochemical cell where $Fe$ is oxidized to $Fe^{2+}$ ($E^\circ = -0.44$ V) and $O_2$ is reduced to $H_2O$ in acidic medium ($E^\circ = +1.23$ V). At a specific point where $pH = 3.0$, $P_{O_2} = 0.2$ atm, and $[Fe^{2+}] = 10^{-6}$ M, calculate the potential ($E_{cell}$) driving the corrosion.

An industrial hydrogen fuel cell operates by reacting $H_2$ and $O_2$ to form water. If the cell consumes $44.8$ L of $H_2$ gas at STP over a period of 1 hour, what is the average current produced by the cell? (Assume 100% efficiency)

During the electrolysis of an aqueous solution of $AgNO_3$ using silver electrodes, a student observes that the mass of the cathode increases by 1.08 g. If the same quantity of electricity is passed through a cell containing $CrCl_3$ solution, what mass of Chromium will be deposited at the cathode? (Atomic masses: $Ag=108, Cr=52$)

Which of the following is not true for a galvanic cell?

What is the value of $n$ in the Nernst equation for the reaction: $Al(s) + 3Ag^+(aq) \rightarrow Al^{3+}(aq) + 3Ag(s)$?

The relation between Gibbs free energy change ($\Delta G$) and cell potential ($E_{cell}$) is:

Which of the following conditions is required for the Standard Hydrogen Electrode (SHE)?

The cell potential of a concentration cell (e.g., $Cu | Cu^{2+}(c_1) || Cu^{2+}(c_2) | Cu$) is positive if:

For the reaction $2AgCl(s) + H_2(g) \rightarrow 2HCl(aq) + 2Ag(s)$, the cell representation is:

If the standard reduction potential of three metals A, B, and C are $+0.5\text{ V}$, $-3.0\text{ V}$, and $-1.2\text{ V}$ respectively, their reducing power order is:

Consider the titration of $Fe^{2+}$ with $Ce^{4+}$ monitored electrochemically. At the equivalence point, the potential of the system is given by the average of the standard reduction potentials of the two redox couples if the stoichiometry is 1:1. Given $E^{\circ}(Fe^{3+}/Fe^{2+}) = 0.77 \text{ V}$ and $E^{\circ}(Ce^{4+}/Ce^{3+}) = 1.61 \text{ V}$, calculate the equilibrium constant $K$ for the reaction $Fe^{2+} + Ce^{4+} \rightleftharpoons Fe^{3+} + Ce^{3+}$ at $298 \text{ K}$.

A fuel cell is being tested for a spacecraft that utilizes the reaction $2H_2(g) + O_2(g) \rightarrow 2H_2O(l)$. If the cell operates at $298 \text{ K}$ with $P(H_2) = 0.5 \text{ atm}$ and $P(O_2) = 0.5 \text{ atm}$, calculate the cell potential $E_{cell}$ given $E^{\circ}_{cell} = 1.23 \text{ V}$. (Use $R = 8.314 \text{ J/mol K}$ and $F = 96485 \text{ C/mol}$)

A technician is calibrating a nickel-cadmium system. For the cell $Cd(s) | Cd^{2+}(0.1 \text{ M}) || Ni^{2+}(0.5 \text{ M}) | Ni(s)$, the standard reduction potentials are $-0.40 \text{ V}$ for $Cd$ and $-0.25 \text{ V}$ for $Ni$. If the temperature rises from $298 \text{ K}$ to $310 \text{ K}$, and assuming $\Delta H^{\circ}$ and $\Delta S^{\circ}$ are constant, calculate the new $E_{cell}$ if $dE/dT = -0.0005 \text{ V/K}$.

The molar conductivity of $CH_3COONa$, $HCl$, and $NaCl$ at infinite dilution are $x, y,$ and $z$ respectively. What is $\Lambda_m^\circ$ for $CH_3COOH$?

Kohlrausch's law can be used to calculate which property of a weak acid?

The molar conductivity of a weak electrolyte is low at high concentration because:

Which of the following factors affects the molar conductivity of a solution?

A $0.01\ M$ solution of $KCl$ has a conductivity of $0.0014\ S\ cm^{-1}$. If its resistance is $200\ \Omega$, the cell constant is $0.28\ cm^{-1}$. What would be the resistance of the same cell filled with $0.02\ M\ KCl$ having conductivity $0.0028\ S\ cm^{-1}$?

The limiting molar conductivity of an electrolyte can be obtained by extrapolating the graph of $\Lambda_m$ vs $\sqrt{c}$ to zero concentration ONLY for:

Which of the following will have the highest molar conductivity at a concentration of $0.01\ M$?

A $0.1\ M$ solution of $KCl$ has a resistance of $100\ \Omega$ in a conductivity cell. The same cell filled with $0.02\ M\ KCl$ has a resistance of $520\ \Omega$. If the specific conductivity of $0.1\ M\ KCl$ is $1.29\ S\ m^{-1}$, calculate the molar conductivity of $0.02\ M\ KCl$.

If the specific conductivity of a saturated solution of $AgCl$ is $2.30 \times 10^{-6}\ S\ cm^{-1}$ and $\Lambda^0_m(AgCl)$ is $138.3\ S\ cm^2\ mol^{-1}$, what is the $K_{sp}$ of $AgCl$ (neglecting the conductivity of water)?

Given that $\Lambda^0_m(HCl) = 426$, $\Lambda^0_m(NaCl) = 126$, and $\Lambda^0_m(NaC_2H_3O_2) = 91\ S\ cm^2\ mol^{-1}$. What is the $\Lambda^0_m$ for acetic acid?

In the electrolysis of an aqueous solution of sodium chloride ($NaCl$), which of the following species is preferentially discharged at the cathode?

Which of the following requires the largest amount of electricity per mole of product?

The device which converts electrical energy into chemical energy is called:

What is the unit of electrochemical equivalent ($Z$)?

In the electrolysis of concentrated $H_2SO_4$ using high current density, the main product at the anode is:

On passing 0.5 Faraday of electricity through $NaCl$ solution, the amount of $Cl_2$ gas evolved is:

During the electrolysis of acidified water, the volume of $H_2$ produced at the cathode compared to $O_2$ at the anode is:

A silver spoon with a surface area of $100\text{ cm}^2$ is to be plated with a $0.01\text{ mm}$ thick layer of gold using an electrolytic bath of $K[Au(CN)_2]$. The density of gold is $19.3\text{ g/cm}^3$. If the plating current is $0.5\text{ A}$, how long (in seconds) must the spoon be kept in the electrolyte? (Molar mass $Au = 197\text{ g/mol}$; Assume $Au$ is in $+1$ state)

An electrochemist performs the electrolysis of a $1.0\text{ M } NaCl$ solution using a mercury cathode (Castner-Kellner process). If the current used is $10\text{ A}$ for $1930\text{ seconds}$, and the cathode is $100\text{ g}$ of pure mercury, what is the mass percentage of sodium in the resulting sodium amalgam ($Na/Hg$)? (Atomic mass: $Na = 23, Hg = 200$)

In a hydrogen-oxygen fuel cell simulation, water is electrolyzed to determine the gas yields. A charge of $0.1\text{ Faraday}$ is passed through an aqueous $H_2SO_4$ solution. Calculate the total volume of all gases evolved at both electrodes combined at STP.

A Nickel-Cadmium cell has a longer life than a lead storage battery but is:

Which metal is used for 'sacrificial protection' to prevent the rusting of iron pipes?

Which of the following is a secondary battery?

The efficiency of a fuel cell compared to conventional thermal plants is approximately:

In a $H_2 - O_2$ fuel cell, which of the following processes occurs at the cathode, and what is the standard reduction potential for the overall cell reaction under standard conditions?

In the electrochemical process of rusting, the $H^+$ ions required for the reduction of oxygen are provided by:

At the anode of a fuel cell, hydrogen gas is oxidized to water in the presence of:

In the context of the Apollo space program's $H_2-O_2$ fuel cells, water produced was used for drinking. If a fuel cell stack produced energy at a rate of 1.23 kW at a constant voltage of 1.0 V for 10 hours, how many liters of pure liquid water would the astronauts have collected? (Assume density of water is 1 g/mL)

A technician is testing an old Dry Cell (Leclanché cell). The cell's voltage has dropped below 1.0 V. Upon inspection, the zinc casing is perforated. This corrosion is a major drawback of the acidic version of this cell. Calculate the mass of Zinc consumed if the cell provided a constant current of 50 mA for 100 hours of cumulative use. (Atomic mass of $Zn = 65.4$)

A deep-sea submersible uses a specialized Silver-Zinc battery. The discharge reaction is $Zn + Ag_2O + H_2O \rightarrow Zn(OH)_2 + 2Ag$. If the cell produces a current of 0.1 A for 24 hours, determine the change in the mass of the $Ag_2O$ cathode material as it is reduced to metallic Silver. (Atomic mass: $Ag = 108, O = 16$)

Corrosion is a spontaneous process. This means that for the corrosion reaction:

Boiled distilled water covered with a layer of oil prevents rusting because:

What happens to the electrons released by iron atoms at the anodic site during rusting?

Which of the following is an example of preventing corrosion by alloying?

Corrosion is essentially the reverse process of:

Which of the following is NOT a product or intermediate in the electrochemical process of iron rusting?

The primary role of 'anti-rust' solutions used in car radiators is to:

Which of the following correctly describes the effect of a 'Differential Temperature Cell' on the corrosion of a single metal pipe?

What is the stoichiometric coefficient of $H_2O$ in the balanced equation for the atmospheric oxidation of $Fe^{2+}$ to rust ($Fe_2O_3 \cdot xH_2O$)?

Identify the primary cathodic reaction for the corrosion of iron in a completely deaerated (oxygen-free) but highly acidic solution.