Consider the following TLC plate, developed in ligroin

The Rf values of A,B, and C are following:

For A:

Rf = distance moved by the compound or spot / distance moved by the solvent.

Rf = 6.4 cm / 8.0 cm= 0.8O

For B:

Rf = distance moved by the compound or spot / distance moved by the solvent.

Rf = 2.1cm / 8.0 cm= 0.26

For C:

Rf = distance moved by the compound or spot / distance moved by the solvent.

Rf = 5.3cm / 8.0 cm= 0.66

Here the Rf of A is 0.8 , B 0.26 and C 0.66

The more polar a compound has the lower Rf value means it is compound B. Because Polar compound want to bond with polar silica, while non-polar compound will move fast with eleuent hence this non-polar has highest Rf value.

The Rf values becomes larger if a more polar solvent (like ethyl acetate) were used in place ligroin. Polar solvent is more proficient at eluting the compounds from the polar adsorbent hence every compound of mixture moves faster, so the distance moved by the compound is becomes larger thus each compound would have a larger R_f value .