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In a thin layer chromatography experiment, a plate of length 8.76 cm was used and a horizontal line was made at 1.09 cm above the bottom of the plate. After running the experiment (developing and drying), a spot was observed at 5.93 cm from the bottom of the plate, and the solvent front was 7.21 cm from the bottom of the plate. What is the Rf value?

Respuesta :

Answer:

Rf value is 0.790

Explanation:

Retention value, Rf value, is defined as the ratio of the distance travelled by compound to the distance travelled by the solvent in the chromatography.

Can be represented as:

Rf = [tex]\frac{dc}{df}[/tex] ,

where,

dc= distance travelled by the compound

df= distance travelled by the solvent

STEP 1

  • The distance travelled by the compound (dc) is calculated as the difference between the spot of compound that appeared on the plate and the horizontal line from the bottom of the plate i.e

                                         5.93-1.09=4.84 cm

  • The distance travelled by the solvent front (df) is calculated as the difference between the solvent front spot and the horizontal line, i.e

                                          7.21-1.09=6.12 cm

STEP 2

Now calculate the Rf vale by substituting the values in the formula:

                                          Rf = [tex]\frac{dc}{df}[/tex]

                                              = [tex]\frac{4.84 cm}{6.12 cm}[/tex]

                                         Rf = 0.790