question_answer

    A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in figure. The filter paper was removed when the water moved near the paper top of the filter paper.                         (i) What would you expect to see, if the ink contains three  different  coloured components? (ii) Name the technique used by the child. (iii) Suggest one more application of this technique.                               [NCERT Exemplar]

Answer:

               (i) The colour component which is more soluble in water dissolves first, rises faster and produces a colour band (spot) on the paper at a higher position. The less soluble colour components dissolve a little later, rise slower and form coloured bands at lower heights. In this way, three different bands will be observed. (ii)  Chromatography (iii) To separate the pigments present in chlorophyll.