chemistry

Silicotungstic acid

Silicotungstic acid 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 Silicotungstic acid rather than just read about it. In short: Silicotungstic acid or tungstosilicic acid is a heteropoly acid with the chemical formula H4[SiW12O40]. It forms hydrates H4[SiW12O40]·nH2O.

Key takeaways

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

Reference excerpt

Silicotungstic acid or tungstosilicic acid is a heteropoly acid with the chemical formula H4[SiW12O40]. It forms hydrates H4[SiW12O40]·nH2O. In freshly prepared samples, n is approximately 29, but after prolonged desiccation, n becomes 6. It is a white solid although impure samples appear yellow. It is used as a catalyst in the chemical industry.

Applications Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene:

C2H4 + CH3CO2H → CH3CO2C2H5 It's also been commercialized for the oxidation of ethylene to acetic acid:

C2H4 + O2 → CH3CO2H This route is claimed as a "greener" than methanol carbonylation. The heteropoly acid is dispersed on silica gel at 20-30 wt% to maximize catalytic ability. It was recently proposed as a mediator in production of hydrogen through electrolysis of water by a process that would reduce the danger of explosion while allowing efficient hydrogen production at low current densities, conducive to hydrogen production using renewable energy.

Synthesis and structure The free acid is produced by combining sodium silicate and tungsten trioxide followed by the treatment of the mixture with hydrochloric acid. The polyoxo cluster adopts a Keggin structure, with Td point group symmetry.

Hazards Silicotungstic acid is an irritating and odorless substance.

References

Illustrations

Worked examples

Example 1 — a first encounter with Silicotungstic acid

Start with the simplest possible case. Write down what Silicotungstic acid 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 Silicotungstic acid 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 Silicotungstic acid 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 Silicotungstic acid

In research: Silicotungstic acid 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 Silicotungstic acid 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: Silicotungstic acid is common in secondary-school and first-year university syllabi. It links to neighbouring topics Coordination complexes, Heteropoly acids, Inorganic compound stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Silicotungstic acid 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 Silicotungstic acid in 20 minutes

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

Frequently asked questions

What is Silicotungstic acid in simple terms?

Silicotungstic acid or tungstosilicic acid is a heteropoly acid with the chemical formula H4[SiW12O40]. It forms hydrates H4[SiW12O40]·nH2O.

Why does Silicotungstic acid 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 Silicotungstic acid?

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 Silicotungstic acid.