Question

The dye from blue fountain pen can be separated by:
(A) Evaporation
(B) Distillation
(C) Chromatography
(D) Separating funnel

Answer 1

Hint: The dye present in the fountain pen ink is in dissolved form. The dye may be a salt form of organic molecule or may not be in salt form. So, we need a technique which can separate a solid from its solution efficiently.

Complete step by step answer:
Here, we need to give a separation method to separate a dye from a blue fountain pen. We know that ink in the fountain pen contains a dye. So, a dye will generally be soluble in the solution which we call ink. So, we need a method which can separate a dye from ink. Let’s take a look at all the methods given in the options one by one.

A) Evaporation can be used to separate solids from its solution. In most of the cases, these solids are salts. A dye molecule can be either a salt or an organic molecule. So, evaporation will not be a proper method to separate a dye.

B) Distillation is a method by which we can separate two liquids which have differences in boiling points. Here, we are not separating a mixture of two liquids. So, this technique cannot be used here.

C) Chromatography is a technique by which we can separate the components in a mixture. Chromatography can be performed on column or paper. Its basic principle is to separate the component depending upon its affinity towards the mobile phase and stationary phase.
- Mobile phase used in chromatography is generally non-polar and stationary phase is polar. The polar molecules will have more affinity towards the polar phase and non-polar molecules will have more affinity towards non-polar phase. By this way, we can separate a mixture of components into a solution. So, this method can be used in separation of a dye from fountain pen ink.

D) Separating funnel is used to separate liquids that have different densities.
So, the correct answer is “Option C”.

Note: Remember that dye molecules are complex organic molecules and they may give certain reactions in excess of heat. That is the reason why we should not use evaporation to separate them.