Electrolysis of Molten NaCl (Downs Process)

2NaCl → 2Na + Cl2

Overview

The Downs process electrolyzes molten NaCl at about 600°C (lowered from 801°C by adding CaCl₂) to produce sodium metal at the cathode and chlorine gas at the anode. A cylindrical iron cathode surrounds a graphite anode, with an iron screen separating products. This is the primary industrial method for producing metallic sodium.

Participants

Role Substance Coefficient State
Reactant Sodium Chloride NaCl 2 (l)
Product Sodium Na 2 (l)

Everyday Example

Sodium metal produced by this process is used to make sodium vapor street lights that give a characteristic yellow glow.

Industrial Importance

The Downs process produces metallic sodium used in the manufacture of sodium peroxide, sodium hydride, and as a coolant in fast breeder nuclear reactors.

Properties

Type
Electrochemical
Reversible
No
Energy
Endothermic
ΔH
822.0 kJ/mol
Catalyst
CaCl₂ (melting point depressant)

Related Reactions

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Frequently Asked Questions

What is the equation for Electrolysis of Molten NaCl (Downs Process)?
The balanced equation is: 2NaCl → 2Na + Cl₂.
What type of reaction is Electrolysis of Molten NaCl (Downs Process)?
Electrolysis of Molten NaCl (Downs Process) is a electrochemical reaction.
Is Electrolysis of Molten NaCl (Downs Process) exothermic or endothermic?
Electrolysis of Molten NaCl (Downs Process) is endothermic (absorbs energy). The enthalpy change (ΔH) is 822.0 kJ/mol.
What conditions are needed for Electrolysis of Molten NaCl (Downs Process)?
This reaction requires a catalyst (CaCl₂ (melting point depressant)).