Thin layer chromatography is used to measure a reaction progress. Before the reaction begins, the starting materials are observed to rise 24 mm, 31 mm and 39 mm on a plate where the solvent front moves 59 mm. Some reaction mixture is analysed after 1 hour, and three spots are again observed, at 27 mm, 35 mm and 44 mm, on a plate where the solvent front moves 66 mm. What could be deduced from these observations?

Question

Quizplus · Accepted Answer

The change in the distances of the spots on the TLC plate indicates that the reaction has occurred. The fact that all three starting materials are still present in the reaction mixture suggests that none of them has been completely consumed - this implies that one of the reactants is in excess. Therefore, option C is correct. Option A can be eliminated because the change in distances of the spots indicates that some reaction has taken place. Option B and D cannot be concluded because the change in distances of the spots does not give information about which spot represents a reactant or a product.

Thin Layer Chromatography Is Used to Measure a Reaction Progress