Sodium citrate is a salt of sodium and citric acid. It can be seen in a range of applications, including food preservation, pharmaceuticals, and laboratory uses.

Physical Properties:

Appearance: Sodium citrate is a white crystalline powder, usually of fine texture. Its crystalline structure makes it solidly stable, thereby easy to handle and keep in stores.

Molecular Weight: 258.06 g/mol; it is a salt of three sodium ions and one citrate ion.

Melting Point: Decomposes approximately at 300 °C or 572 °F. Such a high decomposition temperature indicates that sodium citrate is stable under normal conditions, though it has no definite melting point because of its decomposition.

Solubility: Sodium citrate has a high solubility in water, and it may be formulated as about 1 g/mL at 20 °C. The degree of solubility makes it an excellent agent for the production of buffer solutions and for use in food systems where it acts as a preservative and stabilizer.

Density: The density of sodium citrate is about 1.5 g/cm³ meaning it is more dense than water. It shall therefore be crucial to estimate concentrations in solution.

pH: The pH of a 1% aqueous solution of sodium citrate is mostly neutral to slightly alkaline in the order of pH 5.0 to 7.0. This presents a beneficial range for its application as a buffering agent.

Chemical properties

Acidity and Basicity:

Sodium citrate is the sodium salt of citric acid, it is therefore a weak acid. In aqueous solution, it acts as a buffer, maintaining the pH in a stable state. Since it can only partially dissociate to give up the citrate ions (C₆H₅O₇²⁻), which react with H⁺ ions thereby maintaining a neutral pH.

Dissociation in Water:

When Sodium citrate is dissolved in water, it dissociates into sodium ions (Na⁺) and citrate ions

This dissociation contributes towards its solubility and buffering capacity.

Buffering Capacity:

Sodium citrate is highly used as a buffer in biological and chemical processes. This can be helpful in maintaining a stable pH level within a solution through neutralization of acids or bases, thus being useful for use in laboratory applications as well as food applications.

Reactivity:

Since sodium citrate is a chelating agent, it can interact with acids to provide citric acid along with the respective salts. It is of interest in formulations where some acidity adjustment is required.

Chelation:

Sodium citrate is a chelating agent. Thus, it will readily bind calcium and magnesium metal ions present in solutions. It is used in various applications-from food preservation to pharmaceutical applications to hinder any undesirable interaction of metal ions with other components that are present in the system.

Thermal Stability:

Sodium citrate is stable at room temperatures but decomposes at high temperatures with the evolution of carbon dioxide and sodium carbonate.

Application

Food Industry:

Sodium citrate can be found in the form of a food additive, where it is used as an antiseptic and as a flavoring agent. Sodium citrate can be used to stabilize emulsions; it may also improve texture characteristics when it is used in cheese and dairy products. Further, sodium citrate can act as an acidity regulator to control pH levels in beverages or other food products.

Pharmaceutical:

Sodium citrate is used as an anticoagulant in blood collection tubes; it prevents clotting through bond formation with calcium ions. It also serves as a pH adjuster and solubility increaser for some medications.

Laboratory Applications

Sodium citrate is used as a buffer agent in biochemical and molecular biology experiments. The buffering action maintains a stable pH, very essential for proper enzyme activity and other biochemical processes.

Personal Care Application

Sodium citrate is used in antacids to help in the neutralization of excess acid within the stomach.

Some cosmetics and personal care products contain sodium citrate as a pH adjuster and stabilizer for the product: It is non-caustic and keeps the product working and safe.

Agriculture

It may be used in agriculture to act as a chelating agent so that the availability of micronutrients may be increased for plants.

Conclusion

Sodium citrate is an all-purpose compound used in various industries, such as food, pharmaceuticals, and research. Its chemical properties like buffering capacity, solubility, and the chelation ability make it invaluable in holding any solution together in stability and efficacy. As a preservative for food, an anticoagulant, or used as a laboratory reagent, sodium citrate plays a significant role in improving product performance and safety. In summary, its importance for health and industry raises awareness for the need to know how to understand these properties and the kind of uses that this particular compound may hold.

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Sodium Citrate Formula

Chemical formula: