AIM: To carry out the Qualitative analysis of fourth group compounds
Sample:Amines-Aniline
I. Preliminary Examination
| Experiment | Observation | Inference |
|---|---|---|
| a)Physical State |
Liquids | Aldehyde, ketones alcohols, Phenols, aniline |
| b) Colour | Reddish brown |
Aldehyde, ketones alcohols, Phenols, aniline |
| c) Odour |
Plesant | Esters alcohols and anilines |
| Ignition Test: Ignite a small quantity of the substance taken on nickle spatula |
Burns with smoky flame |
Aromatic Compound |
| Test for Unsaturation Substance + water +0.5ml of sodium carbonate solution + KMnO4 solution drop by drop shake. |
Decolourisitation of KMnO4 |
Unsaturated Comounds |
Detection
of Special Elements (Nitrogen, Sulphur & Halogens) by Lassaigne's
Test Preparations of sodium fusion extract (SFE)
Place a small piece of freshly cut dry sodium in a dry sodium fusion tube and melted to a shining globule. Introduce 2drops of 0.1g of the given substance. Heat the tube gently in the beginning and then strongly to red heat for 1-2minutes. Then plunge the red-hot tube into about 10ml distilled water taken in a mortar. Grind the mixture and filter. The colorless filtrate is called stock solution.
Test for nitrogen, sulphur and halogens are carried out with the stock solution:| Experiment | Observation | Inference |
|---|---|---|
| Test for Nitrogen: 2ml of stock solution+few crystals (0.1-0.2g) of ferrous sulphate, boil gently, cool, acidify with dill H2SO4 till the solution is clear, add neutral FeCl3 |
Blue Or Green Colour |
Nitrogen Present |
| Test for Sulphur: a)2ml of stock solution+ 2-3 drops of freshly prepared sodium nitropusside solution+ 1drop of dil NaOH b) 2ml of stock solution +2-3 drops of lead acetate solution+ 1drop of acetic acid |
No purple colour No brown/Black colour |
Sulphur Absent |
| Test for Halogens: (Cl, Br&I) 1ml of stock solution +1ml of dil HNO₃ boil well, Cool and then add 10% AgNO3 solution |
No Precipitate |
Halogen Absent |
Solubility grouping
| Water | Ether | 5% NaOH |
5% NaHCO₃ | Dil. HCL |
DIl H₂SO₄ | Group |
|---|---|---|---|---|---|---|
| - | - | - | - | + | - | IV |
Report: Given sample is soluble in cold Dil HCl hence belongs to group IV
Qualitative Tests for Aniline
| Experiment | Observation | Infernce |
|---|---|---|
| 1. Acetylation: Substance + acetyl chloride dropwise- shake (dry testtube) |
Vigorous reaction Solid Separates |
1 or 2 Amines Presnet |
| 2. Carbylamine reaction: Substance + 2drops of CHCl₃+ 1ml alcoholic KOH warm |
Unpleasnt odor |
1Amine present |
| 3.Diazotization: Substancein dil. Hcl- Cool to 5C -pinch of NaNO2 Pour the above reaction mixture into ice cold beta Napthol in NaOH |
Orange dye |
Aromatic 1 Amine present |
| 4.Rimins Test: Sample+ 5ml H2O+ ml acetone+ drop of sod. nitropruside solution |
Violet red color develop within a minute |
Aromatic primary amine present |
| 5. Sample+Conc.HCl+sodium nitrite |
Clear yellow solution turns starch iodide paper blue |
Primary aromatic amine present |
Report: The
given sample is reddish brown liquid, aromatic presence of special
elements nitrogen, insoluble in water, soluble in dil HCl belongs to
Group IV, positive for diazotization reaction. May be aromatic primary
amines- Aniline
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