Electrochemistry

Which of the following is the correct half-equation for the discharge of oxygen from water in acidic conditions?

In a school experiment, if the universal indicator in the electrolyte turns purple around the cathode during the electrolysis of brine, it indicates the presence of:

Which of the following is true for the electrolysis of molten aluminum oxide?

If a solution contains $Cl^{-}$ and $OH^{-}$ ions in equal concentrations, which one is typically discharged first at a graphite anode?

A student sets up the electrolysis experiment shown in the diagram. Electrode X is an iron rod and electrode Y is a copper rod. The electrolyte is aqueous copper(II) sulfate ($CuSO_{4}$). Which statement correctly describes the observation or result after the current has passed for some time?

Which of the following is produced at the anode when dilute aqueous $Na_{2}SO_{4}$ is electrolyzed?

What is the main reason why solid ionic compounds do not conduct electricity?

If a metal $X$ forms an oxide with formula $X_{2}O_{3}$, and $0.1\text{ F}$ deposits $1.8\text{ g}$ of $X$, what is the relative atomic mass of $X$?

How many moles of chlorine gas are produced by the electrolysis of molten $NaCl$ if $4.825 \times 10^{4}\text{ C}$ of charge is passed?

What happens to the concentration of the electrolyte during the electrolysis of aqueous $CuSO_{4}$ using copper electrodes?

Which terminal of a battery provides the electrons that flow to the cathode?

In the electroplating of a spoon with silver, what is the oxidation half-reaction?

What is the effect of using a higher concentration of metal ions in the electrolyte?

Which of the following statements about electroplating is FALSE?

What change occurs at the anode during the electroplating of a metal $M$ from an $M^{2+}$ solution?

Which of the following processes is most similar to electroplating in terms of the chemical reactions involved?

During the plating of an object with copper, if the anode is made of graphite instead of copper, what will happen to the $Cu^{2+}$ concentration in the electrolyte?

Which of the following represents the most efficient way to achieve a very thick, stress-free metal deposit in electroplating?

If a constant current of $4.0\ A$ deposits $2.0\ g$ of a divalent metal $M^{2+}$ in $30$ minutes, what is the approximate atomic mass of the metal?

During the electroplating of zinc, the pH of the bath must be carefully controlled. If the bath becomes too acidic (low pH), what is the primary risk?

Which property of the electrodes in a fuel cell is most critical for efficient operation?

What is the standard cell potential ($E^\theta_{cell}$) for a hydrogen-oxygen fuel cell at $298 K$?

Which of the following is a disadvantage of hydrogen fuel cells for portable electronics?

In an acidic hydrogen fuel cell, what species migrates through the electrolyte membrane from the anode to the cathode?

If the partial pressure of $O_2$ gas in a fuel cell is increased, what is the predicted effect on the cell potential according to the Nernst equation (qualitatively)?

What happens to the $pH$ of the electrolyte at the cathode of an acidic hydrogen fuel cell during operation if the water produced is not removed?

Which of the following describes the thermodynamic efficiency of a fuel cell compared to a thermal power plant?

An environmental scientist is calculating the efficiency of a fuel cell vehicle. If the cell consumes $2.0\text{ g}$ of $H_2$ gas and produces $193,000\text{ C}$ of charge, what is the Faraday efficiency relative to the theoretical yield ($A_r$ of $H = 1.0$)?

To improve the kinetics of a hydrogen fuel cell used in a heavy-duty truck, the catalyst surface area is increased. If the operating voltage is $0.70\text{ V}$ and the theoretical $E^\circ$ is $1.23\text{ V}$, what is the 'overpotential' and what does it physically represent in the context of the Cambridge curriculum?

During the testing of a hydrogen fuel cell at high altitudes, the partial pressure of $O_2$ drops. Using the Nernst equation principle (qualitatively), what happens to the cell potential ($E_{cell}$) as the concentration of reactants decreases, and which electrode is primarily affected?