Question

In a thin layer chromatography experiment, a plate of length 9.3 cm was used and a horizontal line was made at 1.45 cm above the bottom of the plate. After running the experiment (developing and drying), a spot was observed at 5.6 cm from the bottom of the plate, and the solvent front was 7.7 cm from the bottom of the plate. What is the Rf value

Answer 1

Answer: The $R_f$ value is 0.664

Explanation:

Distance travelled by solvent front = (7.7-1.45)cm = 6.25 cm

Distance travelled by unknown = (5.6-1.45) cm = 4.15 cm

 The retention factor or the $R_f$ value is defined as the ratio of distance traveled by the unknown to the distance traveled by the solvent front.

$R_f=\frac{\text {distance travelled by unknown}}{\text {distance travelled by solvent}}$

$R_f=\frac{4.15}{6.25}=0.664$

Thus the $R_f$ value is 0.664