Step-by-Step Procedure for Boiling Point Determination

Aim: To determine the boiling point of benzene.

Apparatus: An organic compound, a capillary tube, a thermometer, a kerosene burner, and a fusion tube.

Set up of Experiment: The set up of experiment is shown below:

Preparation and Setup

• Close one end of a capillary tube by holding it in a flame and rotating it for 2-3 minutes.
• Transfer a few milliliters of benzene to a fusion tube.
• Immerse the capillary tube into the liquid in the fusion tube, keeping the seal end up.
• Insert the tube in the holes of an aluminum block and a thermometer in the other hole.
• Ensure that the Benzyldehyde liquid is visible in the fusion tube.
• Heat the container gently over a Kerosene burner or other heat source.
• Observe the temperature using the thermometer and record the temperatures t₁ and t₂.
• Boiling point of benzene can be calculated as the average of t₁ and t₂.

Observation and Result

Temperature observation of benzene is as follow:

Calculation

Mean of temperatures taken from the experiment:

Boiling point = (t₁ + t₂)/2 = (77+79)/2 = 78°C

Boiling point of benzene is found to be 78°C.

Common Error

• Recording a temperature before hot vapors fully immerse the thermometer bulb is a common source of error in boiling point determination.
• Measurement uncertainty, including random and systematic errors, can affect the accuracy of reported boiling points.

Determining the boiling point of organic compounds is essential for understanding their properties and behavior. It is the temperature at which a substance changes its state from liquid to gas. Several factors contribute to the boiling point of organic compounds, including intermolecular forces, molecular weight, and symmetry. In this article, we look into what a boiling point is, organic compounds, how to determine the boiling point of a given compound, precautions, etc.