EXPERINMENT 02
Object
Qualitative analysis of unknown organic compound/s for preliminary tests.
Reference
- Vogel Arthere, Elementary practical organic chemistry, 2nd edition, 1966, published by CBS publisher, page No. 61-64.
- Agarwal O.P., Practical Organic chemistry, published by Krishna educational publisher, Edition 2014, page no. 31-32.
Requirement
Test tube, spatula, different compound, glass-rod etc
Theory
Preliminary qualitative analysis of an unknown organic compound involves initial tests to determine the compound’s general properties and the presence of specific elements and functional groups. These tests include physical examination, solubility tests, and flame tests.
| Test | Observation | Inferences | |
| 1 | (a) Nature | i) Solid | Carbohydrate, acid, phenol, amine , higher hydrocarbon may be present. |
| ii) Liquid | Alcohol , ketone , aldehyde, ester, phenol, amines may be present. | ||
| 2 | (b) Colour | Yellow -Solid | m- Dinitrobenzene, p- Nitro toluene, nitro phenol , nitro aniline |
| Yellow -liquid | Nitrobenzene. | ||
| Brown | P – Toluidine , resorcinol. | ||
| Blackish | α – Naphthol | ||
| Pink | ß – Naphthol | ||
| Buff or reddish | Aniline, phenol, Aromatic amine. | ||
| Colourless | Simple acid , alcohol, ester, ketone aromatic hydrocarbon. | ||
| 3 | Odour | Carbolic | Phenol, cresol. |
| Fishy | Amine | ||
| Sweet pleasant | Ester, alcohol and halogen derivatives. | ||
| Bitter almonds | Nitrobenzene,Benzaldehyde | ||
| Moth balls | Naphthalene | ||
| No particular smell | Aromatic acid ,amide, carbohydrate | ||
| 4 | Flame Test | Sooty flame | Aromatic compound or aliphatic compound containing small proportion of hydrogen e.g . CHCI3,CCI4 |
| Non sooty flame | Aliphatic compound | ||
| Substance chars | Carbohydrate, sulphanilic acid. | ||
| 5 | Test for unsaturation
1. KMnO4 test. Substance + 2 ml of water shake well + 2 drops of dilute KMnO4 solution |
Decolourisation of KMnO4 | Saturated compound. |
| No decolourisation | Unsaturated compound. |
Result: Qualitative analysis of unknown organic compound/s for preliminary tests was done successfully.