chemistry

Trisodium citrate

Trisodium citrate is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Trisodium citrate rather than just read about it. In short: Trisodium citrate is a chemical compound with the molecular formula Na3C6H5O7. It is sometimes referred to simply as "sodium citrate", though sodium citrate can refer to any of the three sodium salts of citric acid.

Key takeaways

Trisodium citrate belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Trisodium citrate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Trisodium citrate from memory before moving on to harder problems.

Reference excerpt

Trisodium citrate is a chemical compound with the molecular formula Na3C6H5O7. It is sometimes referred to simply as "sodium citrate", though sodium citrate can refer to any of the three sodium salts of citric acid. It possesses a saline, mildly tart taste, and is a mild base.

Uses

Foods Sodium citrate is primarily used as a food additive, usually for flavor or as a preservative. Its E number is E331. Sodium citrate is employed as a flavoring agent in certain varieties of club soda. It is common as an ingredient in bratwurst, and is also used in commercial ready-to-drink beverages and drink mixes, contributing a tart flavor. It is found in gelatin mix, ice cream, yogurt, jams, sweets, milk powder, processed cheeses, carbonated beverages, wine, and butter chicken, amongst others. Sodium citrate can be used as an emulsifying stabilizer when making cheese. It allows the cheese to melt without becoming greasy by stopping the fats from separating. This effect makes cheese particularly suitable as a topping for nachos - coincidentally echoing its chemical formula Na3C6H5O7.

Buffering

As a conjugate base of a weak acid, citrate can perform as a buffering agent or acidity regulator, resisting changes in pH. It is used to control acidity in some substances, such as gelatin desserts. It can be found in the milk minicontainers used with coffee machines. The compound is the product of antacids, such as Alka-Seltzer, when they are dissolved in water. The pH range of a solution of 5 g/100 ml water at 25 °C is 7.5 to 9.0. It is added to many commercially packaged dairy products to control the pH impact of the gastrointestinal system of humans, mainly in processed products such as cheese and yogurt, although it also has beneficial effects on the physical gel microstructure.

Chemistry Sodium citrate is a component in Benedict's qualitative solution, often used in organic analysis to detect the presence of reducing sugars such as glucose. It can also be used to prepare inorganic metal citrates such as copper citrate.

Medicine In 1914, the Belgian doctor Albert Hustin and the Argentine physician and researcher Luis Agote successfully used sodium citrate as an anticoagulant in blood transfusions, with Richard Lewisohn determining its correct concentration in 1915. It continues to be used in blood-collection tubes and for the preservation of blood in blood banks. The citrate ion chelates calcium ions in the blood by forming calcium citrate complexes, disrupting the blood clotting mechanism. Recently, trisodium citrate has also been used as a locking agent in vascath and haemodialysis lines instead of heparin due to its lower risk of systemic anticoagulation. In 2003, Ööpik et al. showed the use of sodium citrate (0.5 g/kg body weight) improved running performance over 5 km by 30 seconds. Sodium citrate is used to relieve discomfort in urinary-tract infections, such as cystitis, to reduce the acidosis seen in distal renal tubular acidosis, and can also be used as an osmotic laxative. It is a major component of the WHO oral rehydration solution. It is used as an antacid, especially prior to anaesthesia, for caesarian section procedures to reduce the risks associated with the aspiration of gastric contents.

Boiler descaling Sodium citrate is a particularly effective agent for removal of carbonate scale from boilers without removing them from operation and for cleaning automobile radiators.

See also Monosodium citrate Disodium citrate Citric acid

References

Illustrations

Worked examples

Example 1 — a first encounter with Trisodium citrate

Start with the simplest possible case. Write down what Trisodium citrate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Trisodium citrate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Trisodium citrate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Trisodium citrate

In research: Trisodium citrate appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Trisodium citrate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Trisodium citrate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chelating agents, Citrates, E-number additives, so understanding it makes those chapters shorter.
In everyday life: Look for Trisodium citrate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Trisodium citrate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trisodium citrate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Trisodium citrate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trisodium citrate in simple terms?

Why does Trisodium citrate matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Trisodium citrate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Trisodium citrate.