# Sodium Sulfite

## What is Sodium sulfite?

Sodium sulfite is an inorganic salt with chemical formula Na2SO3. It is also known as Disodium sulfite or Sodium sulfite anhydrous. It is a sodium salt of sulfurous acid. It is white in color and odorless. It has a slightly salty taste and is moderately toxic. It dissolves in water but is insoluble in ethyl alcohol. Its pH value is 9 -10.5

### Sodium sulfite production process –

Laboratory process: Sodium hydroxide solution is reacted with sulfur dioxide gas to give the following:

$2\,NaOH + SO_{2}\rightarrow Na_{2}SO_{3}+H_{2}O$

Industrial process: Sulfur dioxide is reacted with a sodium carbonate solution which generates sodium bisulfite. It is converted to sulfite by reacting with sodium carbonate or sodium hydroxide. The overall reaction is as follows:

$SO_{2} + Na_{2}CO_{3}\rightarrow Na_{2}SO_{3}+CO_{2}$

Sodium sulfite hazards – This compound can be an irritant to the eyes and skin causing inflammation of eyes and skin. Also, it can be an irritant to the respiratory tract which causes irritation in the throat, nose, and breathing problems.

### Properties of Sodium sulfite – Na2SO3

 Na2SO3 Sodium sulfite Molecular Weight/ Molar Mass 126.043 g/mol Density 2.633 g/cm³ Boiling Point Decomposes Melting Point 33.4°C

### Na2SO3 Uses (Sodium sulfite)

• Sodium sulfite is used as an important chemical in the pulp and paper industry.
• It is used in wastewater treatment plants as an oxygen scavenger agent.
• It is used in ore flotation.
• It is used in food preservatives.
• It is used in the oil recovery process.
• It is used as a pesticide controller.
• It is used in manufacturing dyes.
• It is used in the textile industry.
• It is used in the production of detergents.
• It is used in photography in the developing process.