Describe the process to show that the dye used in blue/black ink is a mixture of two or more components.

Take a strip of a special type of filter paper. Draw a line with the help of a pencil approximately one inch above one of the edges. Put a small spot of ink on the centre of line with the help of a thin capillary tube. This strip of paper is then suspended in a beaker or jar containing water so that the line is a little above water level. Here water acts as the mobile phase and strip of paper is the stationary phase. You will find that water rises up the paper by capillary action and flows over the spot. As the water rises up, it takes along with it the dye particles also. The spots of separated coloured compounds would be visible at different heights from the position of initial spot. The number of components in ink dye is equal to the number of spots. Usually a dye is a mixture of two or more coloured compounds.