APPARTUS REQUIRED :
- Test tube
- test tube holder
CHEMICAL REQUIRED:
- dil. NAOHCO3
- alcohol
- ether
- KMNO4
- Fecl3
- fehling’s solution
- organic compound
THEORY:
Functional group is the reactive group of organic compound made by an atom or group of atoms due to which organic compounds displays characteristics behavior. Double bond and triple bonds are also functional groups. It is a site of chemical reactivity in a molecule. Therefore, detection of functional group is essential for the identification of organic compounds and starts from the physical character like color, state, odor, stability, etc. Organic compound may be crystalline, amorphous. Organic compound have different colors like white, red, orange etc. Organic compound have characteristics odor of their own like bitter, pungent, smell, etc. Stability behavior of compound towards various solvents also reveals its nature. Ignition towards various solvents also reveals its nature. Ignition of organic compound gives information about aliphatic, aromatic or presence of some functional group.
OBSERVATION:
Sample no: 01
Physical properties
State: crystalline solid
Color: white
Odor: characteristics smell.
Solubility test of organic compound (O1)
| Cold H2O | Hot H2O | Dil. HCl | Dil. NaOH | Dil.NAHCO3 | Alcohol | Ether |
| + | + | + | + | + | – | – |
Preliminary test of organic compound (01)
| S.N | Experiment | Observation | inference |
| 1. | The solution of organic compound and water was treated with litmus paper | Neutral to litmus | May be aldehyde or ketone. |
| 2. | Ignition test: A pinch of organic compound was taken in a spatula and brunt in a Bunsen burner. | Burnt with non sooty flame | May be aliphatic compound. |
| 3. | Unsaturation test: The solution of organic compound was taken, added water / alcohol and was treated with Bayer’s reagent. | The pink color of KMNO4 got discharged. | May be unsaturated compound. |
| 4. | Dil. NaOH test: The water was added in the sample and then was treated with dil, NaOH. | The substance was insoluble. | May be aldehyde group. |
| 5. | Sodium bicarbonate test: The sample was treated with sodium bicarbonate NaHCO3. | No effervescence was obtained | Absence of carboxylic group(COOH) |
| 6. | FeCl3 test: sample + water / alcohol was treated with 1 2 drops of FeCL3 | The color was not changed | Absence of phenolic group |
| 7. | Fehling’s solution test: Little organic compound was heated with fehling’s solution (A+ B) in a test tube. | Blood red precipitate was formed | .may be aldehyde group |
Confirmatory test for functional group
| S.N. | Experiment | observation | inference |
| 1. | Sehiff’s reagent test: About 1 ml of aqueous or alcohol solution of given compound was shaken by adding 1 ml of Sehiff’s reagent. | Pink color was appeared. | Presence of aldehyde group. |
| 2. | Fehling’s solution test: 2 ml of fehling’s solution A was added in fehling’s solution b until clear blue solution was obtained. 0.2 gm of given compound was added and warmed for few minutes. | A reddish ppt of Cu2O was formed | -CHO group was confirmed. |
| 3. | Tolllen’s reagent test: 1 ml of AgNO3 solution was taken in clear test tube & NaOH was added drop wise. NH4OH was added till precipitated dissolved 0.5 g of given compound was added and warmed. | Silver mirror on the inner wall of test tube was formed | -CHO group was confirmed |
RESULT:
The functional group present in the given organic compound was aldehyde group.
CONCLUSION:
Hence, the functional group present in given organic compound can identified by the help of physical properties, preliminary and confirmatory test.
PRECAUTION:
- Chemical should be handled properly.
- Physical properties should be noted carefully.
- Test tube should be carried out carefully.
- Test tube should be handled by test tube holder.