Sodium Carbonate

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Created by: Team Chemistry -, Last Updated: May 23, 2024

Sodium Carbonate

Sodium carbonate, also known as soda ash or washing soda, is a chemical compound often used in household cleaning. In chemistry, sodium carbonate belongs to a group of compounds known as salts. It appears as a white, odorless powder that dissolves easily in water, creating an alkaline solution. This versatile compound is not only essential in cleaning products but also in processes like glass making and water treatment, making it a valuable substance in both household and industrial applications.

What is Sodium Carbonate?

Sodium carbonate is also known as soda ash or washing soda. It is a chemical compound with the formula Na₂CO₃. It is a white, water-soluble powder used in various household and industrial applications. Sodium carbonate helps in cleaning, softening water, and making glass.

Chemical Names and Formulas

Hill FormulaCNa2O3
NameSoda Ash
IUPAC NameDisodium Carbonate
Alternate NamesCrystol Carbonate, Soda, Sodium Carbonate

Structure of Sodium Carbonate


The structure of sodium carbonate consists of two sodium (Na) atoms, one carbon (C) atom, and three oxygen (O) atoms. These atoms form a stable, ionic compound where the sodium ions (Na⁺) bond with the carbonate ion (CO₃²⁻). In this structure, the carbon atom is centrally located and bonded to three oxygen atoms, forming a triangular arrangement. This configuration helps sodium carbonate dissolve easily in water.

Preparation of Sodium Carbonate

To prepare sodium carbonate, we use the Solvay process, which involves several steps. First, we combine sodium chloride (NaCl) with ammonia (NH₃) and carbon dioxide (CO₂) in water. This reaction forms sodium bicarbonate (NaHCO₃) and ammonium chloride (NH₄Cl).

NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl

Next, we heat the sodium bicarbonate, causing it to decompose into sodium carbonate, water, and carbon dioxide.

2NaHCO₃ → Na₂CO₃ + H₂O + CO₂

This process efficiently produces sodium carbonate, which we then collect and use in various applications, such as cleaning and glass-making.

Physical Properties of Sodium Carbonate

AppearanceWhite, crystalline powder
Melting Point851°C (1564°F)
Solubility in WaterHighly soluble, dissolves easily
Density2.54 g/cm³
TasteAlkaline, mildly bitter
HygroscopicAbsorbs moisture from the air

Chemical Properties of Sodium Carbonate

Reaction with Acids

Sodium carbonate reacts with acids to produce carbon dioxide, water, and a salt. For example, when it reacts with hydrochloric acid, it forms sodium chloride, carbon dioxide, and water.

Na₂CO₃ + 2HCl → 2NaCl + CO₂ + H₂O

Reaction with Water

In water, sodium carbonate dissolves and forms an alkaline solution, releasing hydroxide ions (OH⁻) and carbonate ions (CO₃²⁻).

Na₂CO₃ → 2Na⁺ + CO₃²⁻

Reaction with Bases

Sodium carbonate does not react with strong bases like sodium hydroxide, as both are already basic in nature. However, it can react with weak bases, neutralizing them and forming carbonates or bicarbonates.

Thermal Decomposition

Upon heating, sodium carbonate remains stable up to its melting point. Beyond this, it decomposes to form sodium oxide and carbon dioxide.

Na₂CO₃ → Na₂O + CO₂

Sodium Carbonate Chemical Compound Information

Chemical Identifiers

CAS Registry Number497-19-8
Beilstein Number4154566
PubChem Compound ID10340
PubChem Substance ID24852265
SMILES IdentifierC(=O)([O-])[O-].[Na+].[Na+]
InChI IdentifierInChI=1/CH2O3.2Na/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2/fCO3.2Na/q-2;2m
RTECS NumberVZ4050000
MDL NumberMFCD00003494

NFPA Label

NFPA Health Rating3
NFPA Fire Rating0
NFPA Reactivity Rating0

Difference Between Sodium Carbonate and Sodium Bicarbonate

PropertySodium Carbonate (Na₂CO₃)Sodium Bicarbonate (NaHCO₃)
Chemical FormulaNa₂CO₃NaHCO₃
Common NamesSoda ash, washing sodaBaking soda, bicarbonate of soda
AppearanceWhite, crystalline powderWhite, crystalline powder
pH in SolutionStrongly alkaline (pH ~ 11.5)Mildly alkaline (pH ~ 8.3)
Solubility in WaterHighly solubleModerately soluble
UsesGlass making, cleaning, water softeningBaking, antacid, fire extinguishers
Thermal StabilityStable at high temperaturesDecomposes above 50°C
Reaction with AcidsProduces carbon dioxide, water, and a saltProduces carbon dioxide, water, and a salt
Reaction with BasesDoes not react with strong basesReacts with acids to form carbonates
Molecular Weight105.99 g/mol84.01 g/mol
Decomposition ProductsSodium oxide and carbon dioxide upon strong heatingSodium carbonate, water, and carbon dioxide on heating

Function of Sodium Carbonate

  1. Water Softening: Sodium carbonate softens water by reacting with calcium and magnesium ions, which cause hardness. This reaction forms insoluble compounds that can be removed, making the water more suitable for cleaning.
  2. Cleaning Agent: Sodium carbonate acts as a powerful cleaning agent. It helps break down grease, dirt, and stains, making it effective in laundry detergents and household cleaners.
  3. Glass Manufacturing: In glass manufacturing, sodium carbonate lowers the melting point of silica, making the process more efficient. It helps produce various types of glass, including windows and bottles.
  4. pH Regulation: Sodium carbonate regulates pH levels in pools, ensuring the water remains safe and comfortable for swimming. It increases the pH when it becomes too acidic.
  5. Paper Production: In the paper industry, sodium carbonate processes wood pulp, helping to break down the fibers and produce paper. It acts as a buffering agent during this process.

Uses of Sodium Carbonate


Laundry Detergents

Sodium carbonate is a key ingredient in laundry detergents. It helps remove stains and soften water, making the detergent more effective at cleaning clothes.

Glass Manufacturing

Sodium carbonate is essential in glass manufacturing. It lowers the melting point of silica, making the glass-making process more efficient and cost-effective.

Water Treatment

Sodium carbonate treats hard water by precipitating calcium and magnesium ions. This process softens the water, making it suitable for industrial and household use.

Food Additive

In the food industry, sodium carbonate regulates acidity and acts as a leavening agent. It helps baked goods rise and improves their texture.

Pool Maintenance

Sodium carbonate maintains the pH balance in swimming pools. It raises the pH levels, ensuring the water remains safe and comfortable for swimmers.

Paper Production

Sodium carbonate is used in the paper industry to process wood pulp. It breaks down the fibers and aids in the production of paper, acting as a buffering agent.

Cleaning Agent

Sodium carbonate is a versatile cleaning agent. It is used in various household cleaners to break down grease, dirt, and stains, making surfaces cleaner and brighter.

Side Effects of Sodium Carbonate

  • Skin Irritation: Contact with sodium carbonate can cause redness, itching, and irritation on the skin.
  • Eye Irritation: If sodium carbonate comes into contact with the eyes, it can cause redness, pain, and possible damage to the cornea.
  • Respiratory Issues: Inhaling sodium carbonate dust may lead to coughing, sneezing, and throat irritation.
  • Digestive Problems: Ingesting sodium carbonate can result in nausea, vomiting, and abdominal pain.
  • Alkalosis: Excessive intake may cause an imbalance in the body’s pH levels, leading to symptoms like muscle twitching, hand tremor, and light-headedness.
  • Environmental Impact: Improper disposal can harm aquatic life and disrupt ecosystems due to its high alkalinity.

Is Sodium Carbonate Just Baking Soda?

No, sodium carbonate is not baking soda. Sodium carbonate (Na₂CO₃) is also known as soda ash, while baking soda is sodium bicarbonate (NaHCO₃).

Is Sodium Carbonate Good or Bad for You?

Sodium carbonate is safe in small amounts for household use but can cause irritation or health issues if inhaled, ingested, or contacted in large quantities.

Does Sodium Carbonate Raise pH in Pool?

Yes, sodium carbonate raises the pH in pools, helping to balance the water’s acidity and maintain safe swimming conditions.

What is Common Name of Sodium Carbonate?

The common name of sodium carbonate is soda ash.

What Happens When Sodium Carbonate is Added to Water?

When sodium carbonate is added to water, it dissolves and forms an alkaline solution, releasing sodium ions (Na⁺) and carbonate ions (CO₃²⁻).

Is Na₂CO₃ a Base or Acid?

Na₂CO₃ (sodium carbonate) is a base. It increases the pH of solutions, making them more alkaline.

Does Baking Soda Increase pH?

Yes, baking soda (sodium bicarbonate) increases pH, making solutions less acidic.

What is the pH of Sodium Carbonate in Water?

In water, sodium carbonate has a pH of approximately 11, making the solution highly alkaline.

What is the pH Level of Sodium Carbonate?

The pH level of sodium carbonate is around 11, indicating it is a strongly alkaline substance.

What is Soda Ash Used For?

Soda ash is used in glass manufacturing, water treatment, cleaning products, and as a pH regulator in pools and various industrial processes.

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