Question

Compounds A and B were detected in a mixture by TLC. Rf values for both compounds were calculated. Which of the following Rf values would show the smallest separation between compounds? 0.3 and 0.1 0.2 and 0.1 0.8 and 0.6 0.5 and 0.8 none of these choices

Answer 1

Answer:

0.2 and 0.1

Explanation:

Thin Layer Chromatography (TLC) is a type of separation technique which involves a stationary phase (an adsorbent medium) and a mobile phase (a solvent medium), and is used to separate mixtures of non-volatile compounds based on their relative attractions to either phases, which is determined by their polarity.

The more a compound binds to the adsorbent medium, the slower it moves up the TLC plate. Compounds that are polar tend to move up the TLC plate slower than non-polar compounds, resulting in a lower Rf value for polar compounds and a higher Rf value for non-polar compounds.

Rf (Retention factor) = distance moved by compound/solute

                                     distance moved by the solvent front

Rf values of 0.3 and 0.1 gives a difference of 0.2

Rf values of 0.8 and 0.6 gives a difference of 0.2

Rf values of 0.5 and 0.8 gives a difference of 0.3

Rf values of 0.2 and 0.1 gives a difference of 0.1, therefore the smallest separation between compounds is the one with Rf values of 0.2 and 0.1.