Give —

(a) the principle involved in separation of the mixture

(b) the technique of separation

for dyes of an ink.

(a) Principle involved: Chromatography is a method by which the various components of a mixture e.g., dyes in an ink, are separated due to their difference in the rate of flow over an adsorbent medium.

(b) Technique of separation:

• Stationary phase in chromatography, the adsorbent medium is known as the stationary phase e.g., filter paper made of cellulose.

• Mobile phase the solvent or the solution that moves due to capillary action is known as the mobile phase.

Separation of dyes in ink by paper chromatography. Ink prepared by dissolving different dyes e.g. A, B, C, D in a suitable solvent, is taken.

• A line is drawn with a pencil over a long strip of a filter paper.
• Place the ink spot containing the different dyes on the filter paper.
• The filter paper is then hung with its lower end dipped in a suitable solvent.
• The paper strip with the spot of ink at its end is dipped into the solvent in a way that the spot itself remains above the liquid surface.
• The solvent flows over the ink spot & the various components of the mixture, of dyes in the ink are separated.