Sodium carbonate has many common applications. It is used in the manufacture of soap and paper because it serves as a moderate base. It is used to manufacture of sodium-containing compounds like borax and it is used to soften water and cleaning scale from hard water. Sodium carbonate is also used in glass-making as a flux for silica to lower the melting point. So called soda-lime glass has been the most common form of glass for centuries. Sodium carbonate is often used a source of carbonate to prepare metal carbonates, which can be calcined to prepare nanostructured metal oxides, such as cobalt oxides
, metal-organic frameworks (MOF)
, and metal nanoparticles.
Sodium carbonate is also used as a basic catalyst for the synthesis of carbon aerogels, especially in the sol-gel polycondensation of formaldehyde and resorcinol. 
Sodium carbonate is often used in organic chemistry as a moderately strong base. In many instances it is preferable to sodium hydroxide as a base because it is milder and safer to handle. Some common uses of sodium carbonate in organic chemistry:
- Base of choice for palladium-catalyzed reactions like Suzuki couplings
- Used in reactions, especially alkylation reactions, that require a base to neutralize acids that form during reactions
- Base for aqueous basic washes of organic layer during workup
- Standard for titrations since it is easy to weigh and relatively safe to handle
Sodium carbonate is a widely used reagent in biochemistry as a buffer component in chromatography, capillary electrophoresis, and enzyme catalysis. Scientists have found that cold solutions of sodium carbonate are ideal for the isolation of cell membranes, membrane proteins, and hydrophobic proteins.