ArticleslgStudy

chemistry

Para red

Para red 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 Para red rather than just read about it. In short: Para red (paranitraniline red, Pigment Red 1, C.I. 12070) is a dye. Chemically, it is similar to Sudan I.

Para red — main illustration
Para red — illustration

Key takeaways

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

Reference excerpt

Para red (paranitraniline red, Pigment Red 1, C.I. 12070) is a dye. Chemically, it is similar to Sudan I. It was discovered in 1880 by von Gallois and Ullrich. It dyes cellulose fabrics a brilliant red color, but is not very fast. The dye can be washed away easily from cellulose fabrics if not dyed correctly. Acidic and basic stages both occur during the standard formation of Para red, and acidic or basic byproducts may be present in the final product.

Synthesis Para red is prepared by diazotization of para-nitroaniline at ice-cold temperatures, followed by coupling with β-naphthol:

Regulation Para red is not approved for use in food in any jurisdiction. In 2005, Old El Paso dinner kits were found to be contaminated with the dye and removed from supermarket shelves.

References

External links MSDS at Oxford University

Illustrations

Para red illustration
Para red illustration
Para red: Synthesis of Para Red
Synthesis of Para Red

Worked examples

Example 1 — a first encounter with Para red

Start with the simplest possible case. Write down what Para red 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 Para red 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 Para red 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 Para red

In research
Para red 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 Para red 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
Para red is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2-Naphthols, 4-Nitrophenyl compounds, Azo dyes, so understanding it makes those chapters shorter.
In everyday life
Look for Para red 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.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Para red” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Para red in 20 minutes

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

Frequently asked questions

What is Para red in simple terms?

Para red (paranitraniline red, Pigment Red 1, C.I. 12070) is a dye. Chemically, it is similar to Sudan I.

Why does Para red 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 Para red?

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 Para red.

Tags

  • 2-Naphthols
  • 4-Nitrophenyl compounds
  • Azo dyes

Keep exploring