Deciphering Electrolysis: Sodium Chloride Reimagined
7.2 هزار بار بازدید -
5 سال پیش
-
📢 Receive Comprehensive Mathematics Practice
📢 Receive Comprehensive Mathematics Practice Papers Weekly for FREE 😊
Click this link to get: ▶️▶️▶️ https://iitutor.com/email-list/ ◀️◀️◀️
Explore the fascinating world of electrolysis with our video, "Deciphering Electrolysis: Sodium Chloride Reimagined."
Electrolysis is a chemical process with numerous applications, from predicting electrolysis products in molten salt electrolytes to extracting reactive metals like aluminium, zinc, and sodium. In this video, we dive deep into the science of electrolysis and its incredible potential.
In molten salt electrolytes, we uncover the reduction of metal ions and the oxidation of anions, shedding light on the unique reactions that occur. In aqueous electrolytes, we explore the reduction of metal ions to metal, the generation of hydrogen and oxygen gases, and the fascinating world of reduction potentials.
Discover how electrolysis plays a crucial role in industrial processes, such as the production of sodium hydroxide and the extraction of sodium metal and chlorine gas from molten sodium chloride.
Join us on this educational journey as we demystify electrolysis and reimagine the world of sodium chloride reactions. Don't miss out on the electrifying chemistry behind it all!
Subscribe to our channel for more exciting science content and stay tuned for more captivating videos.
Predicting Electrolysis Products
In molten salt electrolytes (e.g. PbCl2).
• the metal ions (e.g. Pb2+) are reduced to form metal (e.g. Pb) at the cathode
• the anions (eg Cl-) are oxidised (eg to Cl2) at the anode.
In aqueous electrolytes,
• reduction of metal ions to metal or water to hydrogen gas at the cathode
• oxidation of the anions or water to oxygen gas or oxidation of a reactive metal electrode to metal ions at the anode.
The actual products formed in the electrolysis of aqueous electrolytes can be predicted by the use of a table of reduction potentials although these predictions are not always accurate.
Electrolysis has additional applications in the extraction of reactive metals such as aluminium, zinc and sodium, and in the manufacture of many useful chemicals such as sodium hydroxide. Sodium hydroxide is produced industrially by the electrolysis of concentrated sodium chloride solutions. In a similar process, sodium metal and chlorine gas are produced by the electrolysis of molten sodium chloride.
Electrolysis of molten sodium chloride
The external source of electrical energy acts as an ‘electron pump’ and electrons flow from this source into one of the electrodes, thereby giving it a negative charge. Positive sodium ions are attracted to this negative electrode and are reduced when electrons from the electrode are donated to the ions, turning them into sodium atoms. Because reduction has taken place, this electrode is the cathode.
At the same time, the voltage source draws electrons from the other electrode, giving it a positive electric charge. Negative chloride ions are attracted to this positive electrode where they donate electrons and are oxidised. Because oxidation has taken place, this electrode is the anode. Thus, the following reactions have occurred in molten NaCl.
Electrolysis of Aqueous Sodium Chloride Solution
Electrolysis of dilute NaCl solution
The electrolysis of dilute solutions of sodium chloride produces mainly hydrogen gas at the cathode and oxygen gas at the anode. These products are formed rather than sodium and chlorine because water molecules are reduced and oxidised preferentially to sodium and chlorine ions respectively.
As expected hydrogen gas is produced at the cathode.
The reduction potential of water is greater than that of sodium and so water will be reduced at the cathode (negative electrode):
The oxidation potential of water is greater than that of chloride and so water will be oxidised at the anode (positive electrode):
The overall equation becomes:
The electrolysis becomes the same as the decomposition of water and the overall voltage required is greater than 2.06V.
Electrolysis of concentrated NaCl solution
When concentrated solutions of NaCl are used, chloride ions are oxidised at the anode. The products are dependent on the concentrations of the electrolyte solution. At high concentrations of chloride ions, the discharge of chlorine becomes more favourable. The overall cell reaction is given by the equations:
As this is an oxidation-reduction reaction involving the transfer of electrons, the equation can be broken down into two half equations:
Oxidation half-reaction (anode):
Reduction half-reaction (cathode):
The oxidation half-reaction occurs at the anode, which is connected to the positive terminal of the external electricity source. The reduction half-reaction occurs at the cathode, which is connected to the negative terminal. The starting material for the chlor-alkali process is a concentrated solution of sodium chloride called brine.
Click this link to get: ▶️▶️▶️ https://iitutor.com/email-list/ ◀️◀️◀️
Explore the fascinating world of electrolysis with our video, "Deciphering Electrolysis: Sodium Chloride Reimagined."
Electrolysis is a chemical process with numerous applications, from predicting electrolysis products in molten salt electrolytes to extracting reactive metals like aluminium, zinc, and sodium. In this video, we dive deep into the science of electrolysis and its incredible potential.
In molten salt electrolytes, we uncover the reduction of metal ions and the oxidation of anions, shedding light on the unique reactions that occur. In aqueous electrolytes, we explore the reduction of metal ions to metal, the generation of hydrogen and oxygen gases, and the fascinating world of reduction potentials.
Discover how electrolysis plays a crucial role in industrial processes, such as the production of sodium hydroxide and the extraction of sodium metal and chlorine gas from molten sodium chloride.
Join us on this educational journey as we demystify electrolysis and reimagine the world of sodium chloride reactions. Don't miss out on the electrifying chemistry behind it all!
Subscribe to our channel for more exciting science content and stay tuned for more captivating videos.
Predicting Electrolysis Products
In molten salt electrolytes (e.g. PbCl2).
• the metal ions (e.g. Pb2+) are reduced to form metal (e.g. Pb) at the cathode
• the anions (eg Cl-) are oxidised (eg to Cl2) at the anode.
In aqueous electrolytes,
• reduction of metal ions to metal or water to hydrogen gas at the cathode
• oxidation of the anions or water to oxygen gas or oxidation of a reactive metal electrode to metal ions at the anode.
The actual products formed in the electrolysis of aqueous electrolytes can be predicted by the use of a table of reduction potentials although these predictions are not always accurate.
Electrolysis has additional applications in the extraction of reactive metals such as aluminium, zinc and sodium, and in the manufacture of many useful chemicals such as sodium hydroxide. Sodium hydroxide is produced industrially by the electrolysis of concentrated sodium chloride solutions. In a similar process, sodium metal and chlorine gas are produced by the electrolysis of molten sodium chloride.
Electrolysis of molten sodium chloride
The external source of electrical energy acts as an ‘electron pump’ and electrons flow from this source into one of the electrodes, thereby giving it a negative charge. Positive sodium ions are attracted to this negative electrode and are reduced when electrons from the electrode are donated to the ions, turning them into sodium atoms. Because reduction has taken place, this electrode is the cathode.
At the same time, the voltage source draws electrons from the other electrode, giving it a positive electric charge. Negative chloride ions are attracted to this positive electrode where they donate electrons and are oxidised. Because oxidation has taken place, this electrode is the anode. Thus, the following reactions have occurred in molten NaCl.
Electrolysis of Aqueous Sodium Chloride Solution
Electrolysis of dilute NaCl solution
The electrolysis of dilute solutions of sodium chloride produces mainly hydrogen gas at the cathode and oxygen gas at the anode. These products are formed rather than sodium and chlorine because water molecules are reduced and oxidised preferentially to sodium and chlorine ions respectively.
As expected hydrogen gas is produced at the cathode.
The reduction potential of water is greater than that of sodium and so water will be reduced at the cathode (negative electrode):
The oxidation potential of water is greater than that of chloride and so water will be oxidised at the anode (positive electrode):
The overall equation becomes:
The electrolysis becomes the same as the decomposition of water and the overall voltage required is greater than 2.06V.
Electrolysis of concentrated NaCl solution
When concentrated solutions of NaCl are used, chloride ions are oxidised at the anode. The products are dependent on the concentrations of the electrolyte solution. At high concentrations of chloride ions, the discharge of chlorine becomes more favourable. The overall cell reaction is given by the equations:
As this is an oxidation-reduction reaction involving the transfer of electrons, the equation can be broken down into two half equations:
Oxidation half-reaction (anode):
Reduction half-reaction (cathode):
The oxidation half-reaction occurs at the anode, which is connected to the positive terminal of the external electricity source. The reduction half-reaction occurs at the cathode, which is connected to the negative terminal. The starting material for the chlor-alkali process is a concentrated solution of sodium chloride called brine.
5 سال پیش
در تاریخ 1398/07/10 منتشر شده
است.
7,215
بـار بازدید شده