Determination of Boiling point of Ethyl Alcohol

Описание: Procedure to determine the boiling point of Ethyl Alcohol:
1. Close one end of the capillary tube by holding one end in the flame and rotate it for 2-3 minutes.
2. Transfer a few drops of Ethyl alcohol to the fusion tube.
3. Dip the capillary tube into the Ethyl alcohol liquid filled in the fusion tube keeping the sealed end up.
4. Insert the thermometer into one hole of the aluminium block and insert the tube in one of the holes.
5. Make sure that the Ethyl alcohol liquid is visible in the fusion tube after it is put in the hole.
6. Place the Aluminium block on the tripod and begin heating the block with the help of a kerosene burner.
7. Note down the temperature soon as the regular streams of bubbles are seen out of liquid in the fusion tube.
Think!
1. Why do we determine the boiling point of a liquid?
Answer: Every pure compound has specific boiling point. Any impurity will change its boiling point.
2. Why does ethyl alcohol show higher boiling point than acetone?
Answer: Because ethyl alcohol has hydrogen bonding while actone lacks it.
3. If the boiling point of a given liquid is greater than 100 C then which liquid is used in the water bath?
Answer: Conc. H2SO4
4. Why does sea water boil at higher temperature than distill water?
Answer: Because sea water contains many dissolved salts and is not pure while distilled water is pure water.
Do you know?
Read from practical note book page 17
Post lab activities:
1. Why boiling point of water at hilly areas is lower than that at sea level?
Answer: The pressure at hilly area is lower than at sea level. Therefore boiling of water at hills is lower than at sea level.
2. The boiling point of water on a mountain location is found to be less than 100 C. suggest a way to raise the boiling point of water.
Answer: By adding impurity in water, we can increase the boiling point of water. By increasing external pressure boiling point of water is also increased.
3. On the basis of which property, fractions of the mixture of petroleum are separated from each other during petroleum refining?
Answer: Various fractions of petroleum are separated on the basis of the difference in their boiling points.
4. Alcohol is a colorless liquid but red colored alcohol is used in thermometers.
a. What is the purpose of using colored alcohol instead of using any other compound?
Answer: To note the temperature more obviously.
b. Why use of alcohol is referred over mercury in thermometers?
Answer: Because alcohol is more easily available and is cheap.
Brain Teaser!
1. Why food is cooked quickly in pressure cooker?
Answer: Vapour pressure of water increases inside the pressure cooker and its boiling point increases. This makes the food to cook easily.
2. Very often salt is added to water when boiling an egg? Can you think of a reason to do so?
Answer: By adding salt to water, their boiling point increase which makes egg to boil quick.
Viva Voice:
Q1. What is the boiling point of water?
Ans: The boiling point of water = 100°C.
Q2. What is the boiling point of benzene?
Ans: The boiling point of benzene is 78°C.
Q3. What is the boiling point of Benzaldehyde?
Ans: The boiling point of Benzaldehyde is 178°C.
Q.4. Why do Carboxylic acids have a higher boiling point than hydrocarbons?
Ans: Carboxylic acids have the capability of forming hydrogen bonding and these bonds stabilize the molecule, enabling the organic chain to form additional bonds by dispersion forces.
Q.5. What is the boiling point of water in hilly regions?
Ans: It is less than 100°C.
Q.6. What is the boiling point of Ethyl Alcohol?
Ans: The boiling point of Ethyl Alcohol is 78°C.