Demonstrate the qualitative tests for vitamin A in the given sample. Write the aim, principle, procedure, observations, result and precautions.

1. 1 · Aim. To detect vitamin A in the given oil or capsule by the Carr-Price and sulphuric acid tests (demonstration).
2. 2 · Principle. Antimony trichloride, a Lewis acid, removes the -OH group of retinol and forms an unstable blue carbocation (about 620 nm) that fades within seconds. Conc. H₂SO₄ dehydrates vitamin A to a violet colour that turns reddish brown.
3. 3 · Requirements.
   • Sample dissolved in dry, alcohol-free chloroform.
   • Carr-Price reagent (saturated SbCl₃ in chloroform), acetic anhydride, conc. H₂SO₄.
   • Dry test tubes, pipettes with a filler, amber bottle, fume hood.
4. 4 · Procedure.
   • 1 mL sample solution + 1-2 drops acetic anhydride + about 2 mL Carr-Price reagent; watch at once.
   • Blank with chloroform alone.
   • 1 mL sample solution + 1 drop conc. H₂SO₄.
5. 5 · Observation. [Table: Test | Observation | Inference] Carr-Price: fleeting blue, vitamin A present. Blank: no colour. Conc. H₂SO₄: violet turning reddish brown, vitamin A present.
6. 6 · Result. The given sample contains vitamin A.
7. 7 · Precautions.
   • Dry glassware and alcohol-free chloroform.
   • Read the colour immediately.
   • Dim light, fresh solutions; gloves, goggles, fume hood; never pipette by mouth.

Scoring tip: Examiners look for the reagent name, the word 'transient' or 'fades', and the moisture precaution. Draw the observation table neatly.