A student ran two TLC plates of the same compound using the same eluting solvent, but eluting for different amounts of time. The solvent front was marked at 9 cm on the first plate and 13 cm on the second plate. Based on this information, which statement below is true?
a) The Rf value for the compound will be larger on the second
plate than the first.
b) The Rf value for the compound will be smaller on the second
plate then the first.
c) The Rf value will be the same for the compound on both
plates.
d) None of these statements would be true.
Answer is choice c, but can you explain why?
As we know that Rf value is the ratio of distance travelled by spot to distance travelled by solvent. So as solvent will elute upside the spot will also go up. The distance ratio will be same between these two (solvent front and spot). So Rf value will be same for the compound on both plates. Differnces in distance of solvent front to spot do not effect Rf value at all.
A student ran two TLC plates of the same compound using the same eluting solvent, but...