Q.• Prepare a chart of azodyes, colours and its application.

Step 1. Recall what an azo dye is (section 13.7.2). An azo dye is any azo compound -- two aromatic rings joined through a -N=N- (azo) linkage, made by coupling an arene diazonium salt with a reactive aromatic partner (a phenol or an aromatic amine) -- whose extended conjugation gives it a bright, useful colour.

Step 2. Build the chart using this chapter's own named examples, plus a few further well-known azo dyes for a fuller chart. p-Hydroxyazobenzene -- orange -- made from benzenediazonium chloride + phenol (section 13.7.2's own worked example); used illustratively as the simplest azo-coupling product. p-Aminoazobenzene -- yellow -- made from benzenediazonium chloride + aniline (also section 13.7.2's own worked example); a simple aminoazo dye. Methyl orange -- yellow in base / red in acid -- an azo dye built from a diazotised sulfanilic acid coupled with N,N-dimethylaniline (the source's own 'Do you know?' aside); used as an ACID-BASE INDICATOR in titrations, changing colour over the pH range where the azo linkage's own protonation state changes. Congo red -- red/blue (a common further textbook example of a benzidine-based azo dye) -- historically used as a TEXTILE dye for cotton, and, more specifically, as a chemical indicator/stain (its colour change on contact with acid was historically used as a rough acid-detection test on fabrics). Sudan I -- orange-red (a further well-known azo dye) -- historically used as a FOOD colourant/textile and cosmetic colourant, though now restricted in food use in many countries on safety grounds.

Step 3. Present as a simple table. Name | Colour | Application: p-Hydroxyazobenzene | Orange | Illustrative coupling product (dye chemistry). p-Aminoazobenzene | Yellow | Illustrative coupling product (dye chemistry). Methyl orange | Yellow (base) / Red (acid) | Acid-base indicator. Congo red | Red / Blue (pH-dependent) | Textile (cotton) dye, historical acid-test stain. Sudan I | Orange-red | Historical food/textile/cosmetic colourant (now restricted in food).

Building the requested chart from section 13.7.2's own two worked coupling examples plus its 'Do you know?' methyl-orange aside, supplemented with two further well-known azo dyes (Congo red, Sudan I) for a fuller, genuinely useful chart

• Listing only the chapter's own two worked azo-coupling PRODUCTS (p-hydroxyazobenzene, p-aminoazobenzene) without also including methyl orange, missing the chapter's own explicit 'Do you know?' hint that indicator dyes are a real, chapter-relevant azo-dye application.
• Omitting the APPLICATION column the activity specifically asks for, listing only names and colours without saying what each dye is actually used for.