3. Liquid Sample (Aniline, Nitrobenzene, Benzylalcohol

3.1. Physical Character

  • State of aggregation
  • Appearance
  • Color
  • Smell

3.2. Preliminary tests

Experiment Observation Inference
Heat a small portion of the sample in a test tube
  • Evaporates with pungent smell
  • May be acetic acid or formic acid
Treat a small portion of the sample with conc. sulfuric acid and warm gently if necessary.
  • Smell of vinegar
  • Evolves a gas on burning of which, shows pale blue flame
  • May be acetic acid
  • May be formic acid

3.3. Solubility test in water

Experiment Observation Inference
Shake a small portion of the sample with fresh water in a test tube Sample is insoluble in water May aniline nitrobenzene or benzylalcohol

3.4. Acidity of the sample

Experiment Observation Inference

Test a portion of the aqueous solution or suspension with

  • Litmus paper
  • solution of sodium bicarbonate
  • non-acidic to litmus
  • No effervescence occurs
 May be aniline, nitrobenzene or benzylalcohol

3.5. Preliminary conclusion

From the experiments, solubility and acidity it appears that the given sample is Formic acid or Acetic acid.

3.6. Systematic analysis (For sample soluble in water and acidic)

Experiment Observation Inference
Mix a small portion of original sample with a few drops of chloroform and alcoholic KOH. Heat to dryness
  • Bad odor of carbyl amine.
  • No bad odor
  • May be aniline
  • May be nitro- benzene or benzyl alcohol
Reduce the sample with Sn/HCl. Perform dry test.
  • Brick red dye
  • No dye
  • Nitrobenzene
  • Benzyl alcohol

3.7. Confirmatory test

3.7.1. For Aniline

Experiment Observation Inference
Perform dye test A brick red dye Aniline

3.7.2. For Nitro benzene

Experiment Observation Inference
Neutral medium reduction Heat the OS with 50% ethanol, Zn-dust and ammonium chloride. Filter and add Tollens reagent and ward.
  • Grey precipitate
 Nitrobenzene

3.7.3. For Benzyl alcohol

Warm 1-2 drops of O.S. with 2 ml. dil. nitric acid on a water bath.

Heat to boil a solution of 2-3 gm. potassium permanganate in 20 ml water. Add 1 ml O.S. to the hot solution slowly and carefully until the purple color disappears Cool and filter. Acidify the filtrate with conc. HCl and cool it again

A pale yellow emulsion with strong bitter almond odor (benzaldehyde)

A white precipitatte of benzoic acid

 Benzyl alcohol

3.8. Conclusion

  • Name of the given compound
  • Structure of the given compound