Question

Where ink is not heated directly in activity to separate dye from ink?

Answer 1

Take a thin strip of filter paper.
Draw a line on it using a pencil, approximately 3 cm above the lower edge
Put a small drop of ink (water soluble, that is, from a sketch pen or fountain pen) at the centre of the line. Let it dry.
Lower the filter paper into a jar/glass/beaker/test tube containing water so that the drop of ink on the paper is just above the water level, as shown in Fig.4 (b) and leave it undisturbed.
Watch carefully, as the water rises up on the filter paper. Record your observations.
The ink that we use has water as the solvent and the dye is soluble in it. As the water rises on the filter paper it takes along with it the dye particles. Usually, a dye is a mixture of two or more colours. The coloured component that is more soluble in water, rises faster and in this way the colours get separated.
This process of separation of components of a mixture is known as chromatography. Kroma in Greek means colour. This technique was first used for separation of colours, so this name was given.
Chromatography is the technique used for separation of those solutes that dissolve in the same solvent.