Determination of boiling point of given compounds (Ethanol & Acetone)

 Determination of boiling point of given compounds (Ethanol & Acetone)

Abstract

This experiment aims to determine the boiling points of ethanol and acetone using a simple distillation setup. Understanding the boiling points of these compounds is crucial for their applications in laboratory and industrial processes.

Introduction

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the external pressure surrounding the liquid. The determination of boiling points is essential in both the chemical industry and in scientific research, as it helps in identifying substances and assessing their purity. Ethanol and acetone are common solvents in the laboratory. This experiment will provide practical experience with distillation techniques and the handling of these volatile compounds.

Details of the Experiment

Procedure

  1. Set up a simple distillation apparatus with a Bunsen burner, a distillation flask, and a condenser.
  2. Fill the distillation flask with a known quantity of ethanol.
  3. Heat the flask gently and record the temperature at which a steady stream of vapor begins to condense.
  4. Repeat the procedure for acetone.

Observations and Calculations

Record the temperature when the first drop of distillate is collected. This temperature is noted as the boiling point. Repeat the process to confirm consistency in the observed temperatures.

Conclusion

The experimentally determined boiling points for ethanol and acetone should closely match their known boiling points if the procedure is performed correctly and the substances are pure.

Precautions

  • Ensure that the setup is airtight to prevent vapor loss.
  • Avoid overheating to prevent rapid boiling and bumping.
  • Use appropriate safety gear like gloves and goggles during the experiment.

Short Questions with Answers

  1. Define boiling point.
    Answer: Boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid.
  2. What is the purpose of determining the boiling points of substances?
    Answer: To identify substances and assess their purity.
  3. How does the boiling point of a substance relate to its vapor pressure?
    Answer: At the boiling point, the vapor pressure equals the external pressure.
  4. What is the significance of using a known quantity of substance in the distillation flask?
    Answer: To ensure consistent and accurate measurement of the boiling point.
  5. Why is it important to record the temperature when the first drop of distillate is collected?
    Answer: It indicates the boiling point of the substance.
  6. How can impurities affect the boiling point of a substance?
    Answer: Impurities can raise or lower the boiling point depending on their nature relative to the pure compound.
  7. What safety precautions should be followed during distillation?
    Answer: Use protective gear, ensure proper ventilation, and handle flammable substances with care.
  8. What is the purpose of a condenser in distillation?
    Answer: To cool and condense the vapor back into liquid form.
  9. Explain why controlled heating is essential during distillation.
    Answer: To prevent rapid boiling and bumping, ensuring safe and accurate results.
  10. How does the boiling point of ethanol compare to that of acetone?
    Answer: Ethanol has a higher boiling point compared to acetone.
  11. What is the boiling point of ethanol?
    Answer: The boiling point of ethanol is approximately 78.4°C.
  12. What is the boiling point of acetone?
    Answer: The boiling point of acetone is approximately 56.5°C.
  13. What is the role of the Bunsen burner in distillation?
    Answer: To provide heat necessary for vaporization.
  14. Why is it important to ensure an airtight setup during distillation?
    Answer: To prevent the loss of vapors and ensure accurate measurement of boiling points.
  15. What precautions should be taken when handling flammable substances like ethanol?
    Answer: Avoid open flames, use a water bath for heating, and keep away from sources of ignition.
  16. What is the effect of atmospheric pressure on the boiling point of a substance?
    Answer: Higher atmospheric pressure raises the boiling point, and lower pressure lowers it.
  17. Why is it necessary to repeat the distillation process?
    Answer: To confirm the accuracy and consistency of the observed boiling points.
  18. What safety equipment is essential during the distillation process?
    Answer: Safety goggles, gloves, and a lab coat.
  19. What is the primary purpose of using a watch glass in distillation?
    Answer: To prevent the loss of vapors and to observe the distillation process.
  20. What does the distillation process separate?
    Answer: The process separates substances based on differences in their volatilities in a boiling liquid mixture.

Multiple Choice Questions (MCQs) with Answers

  1. What does the boiling point of a liquid indicate?
    • a) The temperature at which the liquid becomes a gas
    • b) The temperature at which the vapor pressure equals atmospheric pressure
    • c) The temperature at which the liquid freezes
    • d) The temperature at which the liquid reacts with air
    • Answer: b) The temperature at which the vapor pressure equals atmospheric pressure
  2. Which of the following is a common use of acetone?
    • a) As a fuel additive
    • b) As a food additive
    • c) As a solvent in nail polish remover
    • d) As a pesticide
    • Answer: c) As a solvent in nail polish remover
  3. Why is acetone preferred as a solvent in many industrial processes?
    • a) Low cost
    • b) Non-toxic nature
    • c) High boiling point
    • d) High solvency for organic compounds
    • Answer: d) High solvency for organic compounds
  4. What is a characteristic property of ethanol?
    • a) It is highly reactive with water
    • b) It has a very high boiling point
    • c) It is miscible with water and organic solvents
    • d) It is a strong acid
    • Answer: c) It is miscible with water and organic solvents
  5. What precaution should be taken when heating flammable liquids like ethanol?
    • a) Heat over an open flame
    • b) Use a water bath to distribute heat evenly
    • c) Heat rapidly to speed up the experiment
    • d) None of the above
    • Answer: b) Use a water bath to distribute heat evenly

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