Class 12 Record Experiment 4

 (WRITE IN LHS)                            Experiment 4                     Paper chromatography 

OBSERVATIONS AND CALCUTATIONS    

SL NO	SUBSTANCE	DISTANCE TRAVELLED BY  DIFFERENT COMPONENTS	DISTANCE TRAVELLED BY  SOLVENT	Rf VALUE (no units)
1	RED + GREEN INK	RED INK ( A cm)      = ………cm	X cm =	A/X = …….
2	RED + GREEN INK	GREEN INK ( B cm) = …….cm	X cm =	B/X = …….

USE THE CHROMATOGRAM YOU GOT FROM EXPERIMENT AND DO CALCULTIONS 

RESULT 

Rf value of red ink   =   

Rf value of green ink   =   

(WRITE IN RHS )               EXPERIMENT 4     PAPER CHROMATOGRAPHY    

AIM :-

 To separate the coloured components, present in the mixture of red and green inks by ascending paper chromatography and find their Rf values

Theory 

Paper chromatography is a type of partition chromatography in which a special adsorbent paper is used instead of a column. Moisture adsorbed by this acts as a stationary phase and the solvent as a moving phase. The basic principle of chromatography is based on the differential migration of the individual components of a mixture through a stationary phase under the influence of moving phase (eluent)

PROCEDURE  

1. Take a Whatman filter paper strip ( 20 × 2cm) and draw a line with pencil above 3cm from one end. Draw another line lengthwise from the centre of the paper.

2. With the help of fine capillary tube, put a drop of the mixture of red and green inks at the point P. Let it dry in air. Put another drop on the same spot and dry again. Repeat 2-3 times, so that the spot is rich in the mixture.

3. Suspend the filter paper vertically in a gas jar containing the solvent (eluent) with the help of glass rod in such a way that the pencil line (and the spot) remains about 2 cm above the solvent level (50% alcohol and distilled water)

4. Cover the jar and keep it undisturbed. Notice the rising solvent along with the mixture of red and green inks. After the solvent has risen about 15cm we will notice two different spots of green and red colours on the filter paper.

5. Take the filter paper out of the jar and mark the distance that the solvent has risen on the paper with a pencil. This is called solvent front.

6. Dry the paper. Put pencil marks in the centre of the green and red spots.

7. Measure the distance of the two spots from the original line and the distance of the solvent from the original line.

8. Calculate the Rf values using the formula.

RESULT 

Rf value of red ink   =   

Rf value of green ink   =