- What is an electrolytic cell?
An electrolytic cell is an electrochemical device that uses electrical energy to drive a non-spontaneous chemical reaction.
- What is the process of using an electrolytic cell called?
The process is called electrolysis.
- What is the role of an external power supply in an electrolytic cell?
The external power supply provides the electrical energy needed to drive the non-spontaneous redox reaction.
- What is an electrolyte?
An electrolyte is a substance that contains mobile ions and conducts electricity.
- What are two types of electrolytes?
Molten electrolytes (e.g., molten sodium chloride) and aqueous electrolytes (e.g., copper(II) sulfate solution).
- Where does oxidation occur in an electrolytic cell?
Oxidation occurs at the anode.
- Where does reduction occur in an electrolytic cell?
Reduction occurs at the cathode.
- What type of charge does the anode have in an electrolytic cell?
The anode has a positive charge in an electrolytic cell.
- What type of charge does the cathode have in an electrolytic cell?
The cathode has a negative charge in an electrolytic cell.
- What is the role of inert electrodes in electrolysis?
Inert electrodes, such as platinum or graphite, do not participate in the reaction but provide a surface for electron transfer.
- What is an active electrode?
An active electrode, such as copper, participates in the electrochemical reaction and may dissolve or deposit metal.
- What happens at the cathode during electrolysis of molten lead(II) bromide?
Pb²⁺(l) + 2e⁻ → Pb(l)
- What happens at the anode during electrolysis of molten lead(II) bromide?
2Br⁻(l) → Br₂(g) + 2e⁻
- What is the overall reaction for the electrolysis of molten lead(II) bromide?
PbBr₂(l) → Pb(l) + Br₂(g)
- What ions are present in an aqueous copper(II) sulfate solution?
Cu²⁺(aq), SO₄²⁻(aq), H⁺(aq), and OH⁻(aq)
- Which ion is reduced at the cathode in the electrolysis of copper(II) sulfate solution?
Cu²⁺(aq) is reduced to Cu(s).
- Which ion is oxidized at the anode in the electrolysis of copper(II) sulfate solution?
OH⁻(aq) is oxidized to O₂(g).
- What are two applications of electrolysis?
Electroplating and extraction of metals.
- How does an electrolytic cell differ from a chemical (galvanic) cell?
An electrolytic cell converts electrical energy to chemical energy, whereas a chemical cell converts chemical energy to electrical energy.
- What is the overall reaction for the electrolysis of hydrochloric acid?
2HCl(aq) → H₂(g) + Cl₂(g)
- Why do cations move to the cathode during electrolysis?
Cations are positively charged and are attracted to the negatively charged cathode, where they gain electrons (reduction).
- Why do anions move to the anode during electrolysis?
Anions are negatively charged and are attracted to the positively charged anode, where they lose electrons (oxidation).
- Why is the electrolysis of aqueous solutions more complex than molten electrolytes?
Aqueous solutions contain both solute ions and water molecules, which can also participate in oxidation and reduction reactions.
- How does the concentration of ions affect electrolysis?
A higher ion concentration increases the likelihood of that ion being discharged at the electrode.
- Why do different ions discharge at different electrodes during electrolysis?
The electrochemical series determines which ions have a greater tendency to be reduced (cathode) or oxidized (anode).
- How does electrolysis help in metal extraction?
Highly reactive metals, such as aluminum and sodium, are extracted from their ores using electrolysis of molten compounds.
- Why is electroplating used in industries?
Electroplating improves the appearance and resistance to corrosion of objects by coating them with a thin layer of metal.
- How is hydrogen gas produced during electrolysis?
Hydrogen gas is produced when H⁺ ions are reduced at the cathode: 2H⁺(aq) + 2e⁻ → H₂(g).
- Why is chlorine gas produced at the anode during the electrolysis of hydrochloric acid?
Chloride ions (Cl⁻) have a higher tendency to be oxidized than OH⁻ ions, forming chlorine gas: 2Cl⁻(aq) → Cl₂(g) + 2e⁻.
- How does the electrochemical series determine electrode reactions?
Species lower in the series are more easily reduced at the cathode, while those higher are more easily oxidized at the anode.