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Sodium Sulphate vs. Sodium Sulphite: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 16, 2023
Sodium sulphate is a stable, inert salt used in detergents and industry, whereas sodium sulphite is a reducing agent used in preserving foods and photography.

Key Differences

Sodium sulphate, with the chemical formula Na2SO4, is known for its inertness and stability under various conditions. It's commonly used in detergents and in the manufacturing of paper and glass. Sodium sulphite, Na2SO3, serves as a reducing agent and preservative, finding its use in food processing and photography due to its ability to react with oxygen.
In the context of industrial use, sodium sulphate is utilized for its non-reactivity, making it suitable for use in large-scale processes like textile and paper manufacturing. Sodium sulphite, on the other hand, is valued for its antioxidant properties, which prevent discoloration and spoilage in food products and photographic materials.
Environmentally, sodium sulphate is relatively benign, with minimal impact on ecosystems. Its role in consumer products like detergents contributes to its widespread use. Conversely, sodium sulphite can be more reactive in the environment and requires careful handling due to its potential to release sulphur dioxide.
In terms of health and safety, sodium sulphate is generally considered safe with low toxicity. It's even used in some medicinal products as a laxative. Sodium sulphite, while also generally safe, can cause allergic reactions in some individuals, particularly those sensitive to sulphites, and is therefore labeled in food products.
Chemically, sodium sulphate is a salt of sulphuric acid, characterized by its high solubility in water and crystal formation. Sodium sulphite, a salt of sulphurous acid, is also soluble in water but is distinguished by its reducing properties, reacting readily with oxygen and other oxidizing agents.

Comparison Chart

Chemical Formula


Industrial Use

Used in detergents, paper, and glass manufacturing.
Used as a reducing agent and preservative in foods and photography.

Environmental Impact

Relatively benign, minimal ecological impact.
More reactive, potential to release sulphur dioxide.

Health and Safety

Generally safe, low toxicity.
Can cause allergic reactions in sulphite-sensitive individuals.

Chemical Properties

Stable, inert salt of sulphuric acid.
Reducing agent, salt of sulphurous acid.

Sodium Sulphate and Sodium Sulphite Definitions

Sodium Sulphate

Sodium sulphate serves as a filler in powdered home laundry detergents.
Sodium sulphate in detergent helps to evenly distribute the active ingredients.

Sodium Sulphite

In photography, sodium sulphite preserves the clarity and quality of images.
Photographers use sodium sulphite in developing solutions to prevent overexposure.

Sodium Sulphate

It is used medicinally as a laxative due to its osmotic properties.
The doctor recommended a sodium sulphate-based product to alleviate constipation.

Sodium Sulphite

Sodium sulphite can release sulphur dioxide, requiring careful handling.
Industries using sodium sulphite implement safety measures to control sulphur dioxide emissions.

Sodium Sulphate

Sodium sulphate is known for forming large crystals, known as Glauber's salt.
Glauber's salt, a form of sodium sulphate, crystallizes in large, clear formations.

Sodium Sulphite

Sodium sulphite is a reducing agent used in preserving foods and in photography.
Sodium sulphite is added to wine to prevent oxidation and preserve flavor.

Sodium Sulphate

It's an inert compound often used in the manufacturing of paper and glass.
The glass industry utilizes sodium sulphate to remove small air bubbles during production.

Sodium Sulphite

It acts as an antioxidant in food, preventing discoloration and spoilage.
Sodium sulphite helps maintain the freshness and appearance of dried fruits.

Sodium Sulphate

Sodium sulphate is a stable, water-soluble salt used in various industrial applications.
Sodium sulphate is added to laundry detergents to improve their cleaning efficiency.

Sodium Sulphite

It is a salt of sulphurous acid, characterized by its chemical reactivity.
The chemical reactivity of sodium sulphite makes it effective in reducing chlorine levels in pools.


Is sodium sulphate harmful to the environment?

Sodium sulphate is generally considered environmentally benign with minimal ecological impact.

Is sodium sulphate soluble in water?

Yes, sodium sulphate is highly soluble in water.

Does sodium sulphate have any medicinal uses?

Yes, sodium sulphate is used as a laxative in some medicinal products.

How does sodium sulphite react with oxygen?

Sodium sulphite reacts with oxygen, acting as a reducing agent.

Can sodium sulphate be used in home laundry detergents?

Yes, sodium sulphate is often used as a filler in powdered home laundry detergents.

What precautions are necessary when handling sodium sulphite?

When handling sodium sulphite, precautions to control sulphur dioxide emissions and avoid allergic reactions are necessary.

What are the key properties of sodium sulphite?

Sodium sulphite is a reducing agent, antioxidant, and preservative, used in foods and photography.

Can sodium sulphite cause health issues?

Sodium sulphite can cause allergic reactions in individuals sensitive to sulphites.

What is the chemical formula of sodium sulphate?

The chemical formula of sodium sulphate is Na2SO4.

What is sodium sulphate primarily used for?

Sodium sulphate is primarily used in industrial applications like detergents, paper, and glass manufacturing.

How is sodium sulphite used in the food industry?

Sodium sulphite is used as a preservative and antioxidant in the food industry to prevent spoilage and discoloration.

Is sodium sulphate reactive like sodium sulphite?

No, sodium sulphate is relatively inert and stable, unlike the more reactive sodium sulphite.

Why is sodium sulphite used in photography?

Sodium sulphite is used in photography to preserve the clarity and quality of images during development.

Can sodium sulphite be used in water treatment?

Yes, sodium sulphite is used in water treatment to reduce chlorine levels.

What differentiates sodium sulphate from sodium sulphite chemically?

Chemically, sodium sulphate is a stable salt of sulphuric acid, while sodium sulphite is a reactive salt of sulphurous acid.

What is a major concern when using sodium sulphite?

A major concern with sodium sulphite is its potential to release sulphur dioxide, which requires careful handling.

What makes sodium sulphate a good additive in industrial processes?

Its stability and inertness make sodium sulphate a good additive in various industrial processes.

What is Glauber's salt?

Glauber's salt is a form of sodium sulphate that crystallizes in large, clear formations.

How does sodium sulphite help in preserving wine?

Sodium sulphite helps in preserving wine by preventing oxidation and preserving flavor.

Are there any environmental concerns with sodium sulphite?

Yes, sodium sulphite can be reactive in the environment, especially concerning its potential to release sulphur dioxide.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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