Photo AI

Describe how the electrolysis of molten sodium chloride produces sodium and evaluate the process to explain why the sodium produced is expensive - OCR Gateway - GCSE Chemistry: Combined Science - Question 14 - 2022 - Paper 1

Question 14

Describe how the electrolysis of molten sodium chloride produces sodium and evaluate the process to explain why the sodium produced is expensive. Use a balanced sym... show full transcript

Worked Solution & Example Answer:Describe how the electrolysis of molten sodium chloride produces sodium and evaluate the process to explain why the sodium produced is expensive - OCR Gateway - GCSE Chemistry: Combined Science - Question 14 - 2022 - Paper 1

Step 1

Describe how the electrolysis of molten sodium chloride produces sodium

96%

114 rated

Answer

The electrolysis of molten sodium chloride (NaCl) involves the decomposition of the ionic compound into its constituent ions. In this process:

Electrolyte State: The sodium chloride must be in a molten state to allow free movement of ions.
Ion Distribution: When a direct current is passed through the molten NaCl, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻).
Electrolysis Reaction at the Electrodes:
- At the cathode (negative electrode), sodium ions gain electrons (reduction) to form sodium metal:
  $ext{Na}^+ + e^- \rightarrow ext{Na}$
- At the anode (positive electrode), chloride ions lose electrons (oxidation) to form chlorine gas:
  $2 ext{Cl}^- \rightarrow ext{Cl}_2 + 2e^-$
Collection of Products: The sodium is produced at the cathode, while chlorine gas is collected at the anode.

Thus, the overall balanced equation for the electrolysis of sodium chloride can be represented as:
$2 ext{NaCl (l)} \rightarrow 2 ext{Na (s)} + ext{Cl}_2 (g)$

Step 2

Evaluate the process to explain why the sodium produced is expensive

99%

104 rated

Answer

The production of sodium through electrolysis is expensive for several reasons:

High Energy Requirements: The electrolysis process requires a significant amount of electrical energy to maintain the molten state of sodium chloride and to drive the chemical reactions. The cost of electricity can be substantial in industrial applications.
High Melting Point: Sodium chloride has a melting point of 801°C, necessitating high-temperature furnaces, which also consume a lot of energy and require highly durable materials to withstand the intense heat.
Production Efficiency: The electrolysis process can have relatively low efficiency due to side reactions and the need for specialized equipment. Maintaining optimal conditions can be costly and complex.
Safety Concerns: Handling sodium and chlorine gas involves significant safety risks, requiring strict protocols and safety measures, which can add to operating costs.

In conclusion, while the electrolysis of molten sodium chloride is an effective method for producing sodium, the associated costs in energy, equipment, and safety make it a relatively expensive process.

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered