Qualitative Analysis of Oils and Fats

Materials Required

Samples

  • Desi ghee
  • Vanaspati ghee
  • Refined oil- Cotton seed oil & Linseed oil

Reagents

  • Water
  • Alcohol
  • Chloroform
  • Potassium bisulphate (KHSO4) crystals
  • Conc. HCl
  • 2% furfural solution in alcohol
  • Huble’s reagent

Apparatus

  • Test tube
  • Dropper
  • Filter paper

Procedure

Real Lab Procedure

Solubility test

Shake a small amount of the given sample with 5 ml each of water, alcohol and chloroform in three test tubes.

Observation and Inference

SI. No.  Solvent  Observation  Inference
1. Water Sample is immiscible. Oil or fat is present.
Sample is miscible. Oil or fat is absent.
2. Alcohol Sample forms a lower layer which dissolves on heating. Oil or fat is present.
Sample does not dissolve even on heating. Oil or fat is absent.
3. Chloroform Sample is miscible. Oil or fat is present.
Sample is immiscible.  Oil or fat is absent.

Transluscent Spot test

Place a little of the substance on a filter paper and press it on the folds of the filter paper and unfold the filter paper.

Observation

SI. No.  Sample  Observation
1.  Desi ghee  Transluscent spot appears on the filter paper.
2.  Vanaspati ghee  Transluscent spot appears on the filter paper.
3.  Refined oil  Transluscent spot appears on the filter paper.

Inference

On unfolding the filter paper, the appearance of transluscent spot on the filter paper indicates the presence of oil or fat.

Acrolein test

Heat a little of the sample with some crystals of potassium bisulphate in a test tube.

Observation

SI. No.  Sample  Observation
1.  Desi ghee  A pungent irritating odour of acrolein.
2.  Vanaspati ghee  A pungent irritating odour of acrolein.
3.  Refined oil  A pungent irritating odour of acrolein.

Inference

A pungent irritating odour of acrolein confirms the presence of oil or fat.

Baudouin test

Take 5 ml of melted ghee in a test tube and add 5 ml of conc. HCl and 2-3 drops of 2% furfural solution in alcohol in it. Shake the test tube well. Keep it aside for 5-10 minutes.

Observation

SI. No.  Sample  Observation
1.  Vanaspati ghee  Rose-red colour appears.
2.  Desi ghee  No formation of rose-red colour.

Inference

Rose-red colour is formed due to the presence of seasame oil. Thus vanaspati ghee contains seasame oil whereas pure desi ghee does not contain seasame oil. So this test is used to distinguish between desi ghee and vanaspati ghee.

Huble’s test

Take two test tubes and label them as I and II. Put 3ml of chloroform into each test tube. Then add 3-4 drops of cotton seed oil into test tube I and linseed oil in test tube II. Shake the test tubes well and add 3 drops of Huble’s reagent in each test tube and observe the fading of violet colour in the test tubes.

Observation

SI. No.  Sample  Observation
1.  Cotton seed oil  Violet colour does not fade away.
2.  Linseed oil  Violet colour fade away.

Inference

The violet colour of iodine fades away in test tube II, while, violet colour in test tube I does not fade away indicating that linseed oil is more unsaturated than cotton seed oil.

Simulator Procedure (as performed through the Online Labs)

You can select the test from ‘Select the test’ drop down list.

Solubility Test

You can select the solvent from ‘Select the solvent’ drop down list.

Water

  • Drag the dropper to the test tube containing desi ghee to drop water into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing vegetable ghee to drop water into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing refined oil to drop water into it.
  • Drag the test tube to shake the contents of the test tube.
  • Click on the inference icon to see the inference.

Alcohol

  • Drag the dropper to the test tube containing desi ghee to drop alcohol into it.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube containing desi ghee to the burner to heat the contents of the test tube.
  • Drag the dropper to the test tube containing vegetable ghee to drop alcohol into it.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube containing vegetable ghee to the burner to heat the contents of the test tube.
  • Drag the dropper to the test tube containing refined oil to drop alcohol into it.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube containing refined oil to the burner to heat the contents of the test tube.
  • Click on the inference icon to see the inference.

Chloroform

  • Drag the dropper to the test tube containing desi ghee to drop chloroform into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing vegetable ghee to drop chloroform into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing refined oil to drop chloroform into it.
  • Drag the test tube to shake the contents of the test tube.
  • Click on the inference icon to see the inference.

Translucent Spot Test

You can select the sample from ‘Select the sample’ drop down list.

Desi Ghee

  • Drag the dropper to the first filter paper to drop desi ghee into it.
  • Drag the second filter paper towards the filter paper containing the sample to press the sample with it.
  • Drag the filter paper towards the lighting candle.
  • Move the filter paper over the flame, the light will be visible only through the spot formed by the ghee.
  • Click on the inference icon to see the inference.

Vanaspati Ghee

  • Drag the dropper to the first filter paper to drop vanaspati ghee into it.
  • Drag the second filter paper towards the filter paper containing the sample to press the sample with it.
  • Drag the filter paper towards the lighting candle.
  • Move the filter paper over the flame, the light will be visible only through the spot formed by the ghee.
  • Click on the inference icon to see the inference.

Refined Oil

  • Drag the dropper to the first filter paper to drop refined oil into it.
  • Drag the second filter paper towards the filter paper containing the sample to press the sample with it.
  • Drag the filter paper towards the lighting candle.
  • Move the filter paper over the flame, the light will be visible only through the spot formed by the oil.
  • Click on the inference icon to see the inference.

Acrolein Test

You can select the sample from ‘Select the sample’ drop down list.

Desi Ghee

  • Drag the spatula to the test tube to put potassium bisulphate crystals into desi ghee.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube to the burner to heat the contents of the test tube.
  • Click on the inference icon to see the inference.

Vanaspati Ghee

  • Drag the spatula to the test tube to put potassium bisulphate crystals into vanaspati ghee.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube to the burner to heat the contents of the test tube.
  • Click on the inference icon to see the inference.

Refined Oil

  • Drag the spatula to the test tube to put potassium bisulphate crystals into refined oil.
  • Click on the knob of the burner to turn it on.
  • Drag the test tube to the burner to heat the contents of the test tube.
  • Click on the inference icon to see the inference.

Baudouin Test

  • Drag the dropper to the test tubes to drop Conc. HCl into desi ghee and vanaspati ghee respectively.
  • Drag the dropper to the test tubes to drop 2% furfural solution in alcohol into desi ghee and vanaspati ghee respectively.
  • Wait for some time to complete the reaction.
  • Click on the inference icon to see the inference.

Hubble's Test

  • Drag the dropper to the test tube containing cotton seed oil to drop chloroform into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing cotton seed oil to drop Hubble's reagent into it.
  • Drag the dropper to the test tube containing linseed oil to drop chloroform into it.
  • Drag the test tube to shake the contents of the test tube.
  • Drag the dropper to the test tube containing linseed oil to drop Hubble's reagent into it.
  • Click on the inference icon to see the inference.

To redo the experiment, click on the ‘Reset’ button.

Note: Click on the ‘HELP’ button to see the instructions.

Precautions

  • Handle the chemicals with care.
  • Use lab coats and gloves while performing the experiment.
  • Use droppers to take the reagents.

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