Aim: To determine of boiling point of Benzene.
Principle: In a liquid, the particles are not arranged in a regular manner and thus free to move. A liquid boil when a temperature is reached at which the thermal energy of the particles is great enough to overcome the cohesive forces that hold them together. This is the point at the vapor pressure of the liquid becomes equal to the atmosphere pressure. Boiling point of the liquid is significant for a compound. The boiling point of organic compound can give important information about their physical properties and structural characteristics. Boiling point helps identify and characterize a compound. A liquid boil when its vapor pressure is determined by the kinetic energy of a molecule.
Kinetic energy depends on the temperature, mass, and velocity of a molecule. When the temperature reaches the boiling point., The average kinetic energy becomes enough to overcome the force of attraction between enough to overcome the force of attraction between the liquid particles. As the force of attraction decreases, the molecules in the liquid state escape from the surface and turn into gas.
The boiling point of a liquid varies with with the surrounding atmospheric pressure has a higher pressure has a higher boiling point than when that liquid is a lower atmospheric pressure has a higher boiling point than when that liquid is a lower atmospheric pressure.
The normal boiling point of a compound is an indicator of the volatility of that compound. The higher the boiling point, the less volatile is the compound.Co reversely, the lower the boiling point, the more highly volatiles the compound will generally exist as a gas at atmospheric pressure. If the boiling point of the compound is higher, it then exists as a liquid or a solid.
Requirements:
Chemicals:
- Benzaldehyde
- Distilled water
- Parafin Liquid.
Glassware/Apparatus:
- Theils tube
- Test tube
- Bunsen Burner
- Tripod stands with clamp
- Gauze
- Capillary tube
- 300°C temperature
- Test tube and bungs
- Oil bath
- Water bath
- Watch.
Apparatus setup of boiling point determination:
Procedure:
- Take a Capillary tube and and close its one end by holding the end in the flame and rotate it for 2-1 minutes.
- Transfer a few ml of benzene in the fusion tube.
- Dip the capillary tube into the liquid in the fusion tube keeping the sealed end up
- insert the tube in one of the holes of aluminum's block and insert the thermometer in the other hole.
- Make sure that the liquid is visible in the fusion tube after it is put in the hole
- Place the aluminum block on the tripod.
- Start heating the block with the help of kerosene burner.
- Note down the temperature soon as the regular steams bubbles are seen out of liquid in the fusion tube.
Observation:
| Temperatu rer|(T-1 |
Temperatu re(T--2 |
Difference between (T-1)+(T-2)/2 |
|
|---|---|---|---|
| B.P of Benzaldehyde |
Results: The Boiling point of the given sample was found as______
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