chemistry

Water blue

Water blue 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 Water blue rather than just read about it. In short: Water blue, also known as aniline blue, Acid blue 22, Soluble Blue 3M, Marine Blue V, or C.I. 42755, is a chemical compound used as a stain in histology. Water supply blue stains collagen blue in tissue sections.

Key takeaways

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

Reference excerpt

Water blue, also known as aniline blue, Acid blue 22, Soluble Blue 3M, Marine Blue V, or C.I. 42755, is a chemical compound used as a stain in histology. Water supply blue stains collagen blue in tissue sections. It is soluble in water and slightly soluble in ethanol. Water blue is also available in mixture with methyl blue, under the names Aniline Blue WS, Aniline blue, China blue, or Soluble blue. It can be used in the Mallory's trichrome stain of connective tissue and Gömöri trichrome stain of muscle tissue. It is used in differential staining. Water blue was first discovered in 1834 when German chemist Friedlieb Ferdinand Runge isolated it from coal tar using chloride of lime. Runge named the dye kyanol or cyanol. Water blue was the first coal tar dye ever to be discovered.

Illustrations

Worked examples

Example 1 — a first encounter with Water blue

Start with the simplest possible case. Write down what Water blue 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 Water blue 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 Water blue 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 Water blue

In research: Water blue 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 Water blue 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: Water blue is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acid dyes, Anilines, Benzenesulfonates, so understanding it makes those chapters shorter.
In everyday life: Look for Water blue 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 Water blue in 20 minutes

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

Frequently asked questions

What is Water blue in simple terms?

Why does Water blue 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 Water blue?

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 Water blue.