The commercial method of preparation of potassium by reduction of molt...
Commercial Preparation of Potassium
The commercial method of preparing potassium involves the reduction of molten potassium chloride (KCl) using metallic sodium at a high temperature of 850°C. This process is underpinned by several key factors related to the properties of potassium and sodium.
Reason for the Process: Volatility of Potassium
- Potassium (K) is more volatile than sodium (Na). At 850°C, potassium has a tendency to vaporize due to its lower boiling point compared to sodium.
- As the reaction proceeds, potassium is produced and quickly vaporizes, allowing it to be collected separately. This vaporization shifts the reaction equilibrium to favor the production of more potassium.
Reaction Dynamics
- The reduction reaction can be represented simplistically as follows:
KCl (molten) + Na → K (vapor) + NaCl
- The formation of gaseous potassium effectively reduces the concentration of potassium ions in the molten salt mixture, thereby driving the reaction forward according to Le Chatelier's principle.
Role of Sodium
- Sodium, being more reactive than potassium, is capable of reducing KCl to potassium. However, it does not vaporize at the same rate, thus remaining in the system to continue the reduction process.
Conclusion
- The selection of 850°C is crucial as it provides the required thermal energy for the reaction while enabling the potassium to distill off, ensuring a continuous removal and further production of potassium.
In summary, the commercial preparation of potassium by reducing molten KCl with sodium is primarily based on the volatility of potassium, which allows for its effective separation and continuous production.
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