Final answer:
In TLC, the compound that travels least is more non-polar, interacting weakly with the mobile phase. Without the image, determining the most non-polar compound or the specific error is impossible. Reverse phase HPLC principles indicate that non-polar compounds have stronger stationary phase interactions, eluting slower.
Step-by-step explanation:
In Thin Layer Chromatography (TLC), the compound that travels the least distance from the baseline is typically more non-polar, because a non-polar compound has a weaker interaction with the polar solvent used in the mobile phase, resulting in slower migration up the TLC plate. Without seeing the described TLC plate, we can establish this principle. As for the error in the TLC plate, if multiple compounds were spotted in lane 3, you would see multiple distinct spots rather than a single spot, indicating separation of compounds. If the sample spotted in lane 3 was too concentrated, the spot might appear larger or more diffuse. If the eluent used was too polar for the compounds being separated, they might all travel very close to the solvent front, making it difficult to differentiate between them. Therefore, without an image, it's impossible to definitively identify which error was made or which lane contains the most non-polar compound.
The use of reverse phase HPLC can similarly provide insights into compound polarity. The technique utilizes particles made of silica coated with alkane chains as a stationary phase. In this technique, hydrophobic or non-polar compounds are more strongly attracted to the stationary phase compared to hydrophilic or polar compounds. Therefore, non-polar compounds would elute slower from the column. The attachment of alkane chains to the silica particles increases the hydrophobic interactions with non-polar solutes, causing them to spend more time in the stationary phase.