chemistry

Sodium tungstate

Sodium tungstate 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 Sodium tungstate rather than just read about it. In short: Sodium tungstate is the inorganic compound with the formula Na2WO4. This white, water-soluble solid is the sodium salt of tungstic acid.

Key takeaways

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

Reference excerpt

Sodium tungstate is the inorganic compound with the formula Na2WO4. This white, water-soluble solid is the sodium salt of tungstic acid. It is useful as a source of tungsten for chemical synthesis. It is an intermediate in the conversion of tungsten ores to the metal.

Preparation and structure Sodium tungstate is obtained by digestion of tungsten ores, the economically important representatives of which are tungstates, in base. Illustrative is the extraction of sodium tungstate from wolframite:

Fe/MnWO4 + 2 NaOH + 2 H2O → Na2WO4·2H2O + Fe/Mn(OH)2 Scheelite is treated similarly using sodium carbonate. Sodium tungstate can also be produced by treating tungsten carbide with a mixture of sodium nitrate and sodium hydroxide in a fusion process which overcomes the high exothermicity of the reaction involved. Several polymorphs of sodium tungstate are known, three at only one atmosphere pressure. They feature tetrahedral orthotungstate dianions but differ in the packing motif. The WO2−4 anion adopts a structure like sulfate (SO2−4).

Reactions Treatment of sodium tungstate with hydrochloric acid gives the tungsten trioxide or its acidic hydrates:

Na2WO4 + 2 HCl → WO3 + 2 NaCl + H2O Na2WO4 + 2 HCl → WO3·H2O + 2 NaCl This reaction can be reversed using aqueous sodium hydroxide.

Uses The dominant use of sodium tungstate is as an intermediate in the extraction of tungsten from its ores, almost all of which are tungstates. Otherwise sodium tungstate has only niche applications. In organic chemistry, sodium tungstate is used as catalyst for epoxidation of alkenes and oxidation of alcohols into aldehydes or ketones. It exhibits anti-diabetic effects. Solutions of sodium and lithium metatungstates are used in density separation. Such solutions are less toxic than bromoform and methylene iodide, but still have densities that fall between a number of naturally coupled minerals. Sodium tungstate is a competitive inhibitor of molybdenum; because tungsten is directly below molybdenum on the periodic table, it has similar electrochemical properties. Dietary tungsten reduces the concentration of molybdenum in tissues. Some bacteria use molybdenum cofactor as part of their respiratory chain; in these microbes, tungstate can replace molybdenum and inhibit the generation of energy by aerobic respiration. As such, one niche use of sodium tungstate is in experimental biology—where it has been found that adding sodium tungstate to the drinking water of mice inhibits the growth of Enterobacteriaceae (a family of endogenous opportunistic pathogens) in the gut. Sodium tungstate has been researched as a potential treatment for infertility under the code OXO-001.

References

Illustrations

Worked examples

Example 1 — a first encounter with Sodium tungstate

Start with the simplest possible case. Write down what Sodium tungstate 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 Sodium tungstate 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 Sodium tungstate 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 Sodium tungstate

In research: Sodium tungstate 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 Sodium tungstate 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: Sodium tungstate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Sodium compounds, Tungstates, Tungsten mining, so understanding it makes those chapters shorter.
In everyday life: Look for Sodium tungstate 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 Sodium tungstate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sodium tungstate 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 Sodium tungstate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sodium tungstate in simple terms?

Sodium tungstate is the inorganic compound with the formula Na2WO4. This white, water-soluble solid is the sodium salt of tungstic acid.

Why does Sodium tungstate 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 Sodium tungstate?

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 Sodium tungstate.