Question

You can try chromatography to find the number of components present in a food colour (green, orange, yellow, etc.) or in coloured mouth fresheners (fennel seeds).

Answer 1

Aim: To find the number of components present in food colours or coloured mouth fresheners using paper chromatography.

Principle: Paper chromatography separates mixtures into their individual components. Different substances travel at different speeds on paper depending on their solubility in the solvent and affinity for the paper, forming separate coloured spots.

Materials Required: 

• Chromatography paper or filter paper
• Food colour solution/crushed mouth freshener (fennel seeds, coloured supari, etc.)
• Water or alcohol (solvent)
• Beaker
• Capillary tube or dropper
• Pencil

Procedure: 

• Take a strip of chromatography paper and draw a pencil line near the bottom.
• Place a small drop of the food colour or extract of mouth freshener on the line.
• Allow it to dry and repeat to make a concentrated spot.
• Pour a small amount of solvent (water or alcohol) into a beaker.
• Suspend the paper so that the spot is above the solvent level.
• Leave it undisturbed and observe as the solvent rises.

Observation: 

• The single coloured spot separates into multiple spots or bands.
• Different colours move different distances up the paper.