AIM : Determining the melting point of a given organic compound.

APPARATUS REQUIRED : Organic compound samples , kjehldahl's apparatus , Thermometer , bunsen burner , Stirring rod , Safety goggles and gloves.

THEORY:

Why is it important to know the melting point of an organic compound? Or we can ask what are the applications of this physical property?

• As already said, it is the physical property of a compound and hence is significant for its characterization or simply put helps in identifying the compound among various possible candidates.

• Another important utility is that it acts as a criteria of purity!!

This takes us to the concept of colligative properties, where we learnt Depression in freezing point and Elevation in boiling point when an insoluble solute is present. Therefore, you would remember that a pure substance shows depression in freezing point (or its melting point) when some impurity is present.

Thus, when we crystallize a solid to purify it, what will happen??

It’s melting point would increase to its actual value (as it is now purer). This is useful for identifying the purity of a sample by comparing it’s recorded melting point with the literature value (verified value in existing records such as journals).

PROCEDURE :

Sample Preparation:

Weigh the Sample: Use a balance to weigh a small amount (a few milligrams) of the organic compound.

Sealing of capillary : use bunsen burner to seal one end of capillary.

Capillary Tube Method: Pack the sample tightly into one end of a thin-walled capillary tube. Tap it gently to ensure it settles.

Set Up the Melting Point Apparatus:

we had taken thermometer , then i dipped it in sulfuric acid of kjehldahl's apparatus.

then i had taken thermometer out and attached capillary to thermometer.

then i put thermometer slowly into the conical flask so that it doesn't touches surface of conical flask.

Heating:

I Gradually heat the sample. I ensured even heating.

I  was Monitor the temperature closely using a thermometer.

Observe the Melting Process:

As the temperature rises, first signs of melting showed(the solid will start to change to liquid).

then I Record the temperature at which the sample first begins to melt (this is the melting point).

Continue to heat and record the temperature at which the entire sample has melted.

Repeat:

For accuracy, I  repeat the experiment 2-3 times with fresh samples to confirm the melting point.

Clean Up:

Dispose of the samples and clean your workspace according to safety guidelines.

OBSERVATIONS:

Sample 1: 122c

Sample  2: 124c

Sample 3: 126c

Observed melting point (first signs and complete melting): 124C

Average melting point : 124C

RESULTS:

melting point of given organic compound is 124C.

SAFETY PRECAUTIONS:

Wear safety goggles and gloves throughout the experiment.

during heating sand bath must be present below bunsen burner as precaution.

capillary must be sealed completely for accurate melting point.