Question

Difficulty: MediumIndustrial Applications of Electrolysis

Match each industrial electrolytic process on the left with its corresponding chemical characteristic or operating condition on the right.

  • Hall-Héroult ProcessElectrolysis of molten alumina dissolved in molten cryolite using carbon electrodes
  • Electrorefining of CopperImpure metal serves as the dissolving anode while pure metal deposits at the cathode
  • Electroplating of Iron with SilverThe article to be coated serves as the cathode in an electrolyte containing silver ions
  • Chlor-Alkali ProcessElectrolysis of concentrated brine yielding chlorine gas, hydrogen gas, and sodium hydroxide

Answer

Hall-Héroult Process matches with 'Electrolysis of molten alumina dissolved in molten cryolite using carbon electrodes'. Electrorefining of Copper matches with 'Impure metal serves as the dissolving anode while pure metal deposits at the cathode'. Electroplating of Iron with Silver matches with 'The article to be coated serves as the cathode in an electrolyte containing silver ions'. Chlor-Alkali Process matches with 'Electrolysis of concentrated brine yielding chlorine gas, hydrogen gas, and sodium hydroxide'.
Each industrial process relies on specific redox reactions and cell configurations: Hall-Héroult process uses molten cryolite as a solvent for alumina; copper refining uses impure copper as the dissolving anode; electroplating places the article to be coated at the cathode; chlor-alkali electrolyzes brine to yield chlorine, hydrogen, and sodium hydroxide.

Step-by-Step Solution

1
Identify the key components and conditions of aluminium extraction.
Aluminium is extracted by electrolyzing molten alumina (Al2O3Al_2O_3) dissolved in cryolite (Na3AlF6Na_3AlF_6) to lower its melting point.
This corresponds to the Hall-Héroult process operating condition.
2
Identify the electrode roles in metal purification.
Impure metal dissolves at the anode and deposits as pure metal at the cathode.
This defines electrorefining of copper.
3
Identify the arrangement for electroplating.
The target object to be coated forms the cathode where metal cations are reduced.
This describes the electroplating of iron with silver.
4
Identify the reactants and products of brine electrolysis.
Concentrated NaClNaCl solution electrolyzed gives Cl2Cl_2, H2H_2, and NaOHNaOH.
This defines the chlor-alkali industrial process.

Key Concept

Industrial applications of electrolysis including metal extraction, refining, electroplating, and chlor-alkali synthesis
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