Question

Red ink is prepared from

• A. Eosin
• B. Phenol
• C. Aniline
• D. Congo red

Answer 1

The correct option is A

Eosin

The explanation for the correct option:

Option (A): Eosin

1. Dyes are organic compounds that are used to color paper, leather, and textiles.
2. Red ink is the most widely used dye for staining cytoplasm in histology. The cytoplasm is the thick fluid that fills the cells.
3. It is a brilliant pink dye substance with a complicated structure that is not found naturally but is manufactured from xanthene.
4. Eosin, a sodium salt known as $2,4,5,7$Tetrabromofluorescein.
5. It is also employed as a red dye in inks however, the molecule, particularly eosin Y, degrades over time, leaving behind its bromine atoms, leading paint containing such a dye to have a darker brown color.

The explanation for the incorrect option:

Option (B): Phenol:

1. The aromatic organic chemical phenol (also known as carbolic acid) has the molecular formula${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH}$. It is a flammable white crystalline substance.
2. Its structure is given as
3. A phenyl group (${\mathrm{C}}_6{\mathrm{H}}_5$) is connected to a hydroxy group ($\mathrm{OH}$) in this molecule. It's mildly acidic and should be handled with caution because it can cause chemical burns.
4. It is largely utilized in the production of plastics and other products. Polycarbonates, epoxies, Bakelite, nylon, detergents, herbicides, and a variety of pharmaceutical medications all require phenol and its chemical derivatives.

Option (C): Aniline

1. The organic compound aniline has the formula${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2$. Aniline is the simplest aromatic amine, consisting of a phenyl group connected to an amino group.
2. Its structure is given as
3. It is primarily used in the production of polyurethane, dyes, and other industrial chemicals as a precursor.

Option (D): Congo red

1. Congo red is the first synthetic dyestuff of the direct kind, meaning it does not require the use of a mordant (a substance such as tannin or alum used to fix the color to cotton fibers).
2. Its structure is given as
3. It is an azo dye made from benzidine.
4. It was once used to color cotton, but it has since been replaced by dyes that are lighter and wash-resistant. It is still used to stain tissues for microscopic examination and as an acid-base indicator in histology.
5. It is not used to make red ink.

Therefore, Red ink is prepared from option (A) Eosin.