REQ.PRAC of paper chtomatography

Question 1

method

Answer 1

1) draw a ‘start line’ in pencil, on a piece of absorbent paper
2) put samples of five known food colourings (A B C D E) and unknown (X) on start line
3) dip paper in solvent and make sure that the solvent only touches the area below the pencil mark
4) wait for solvent to travel to top of paper
5) identify substance X by comparing horizontal spots with results of A B C D E

Question 2

considerations

Answer 2

• pure substances produce a single spot in all substances

- only use pencil as ink will dissolve and affect results